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https://proteopedia.org/api.php?action=feedcontributions&feedformat=atom&user=Andrew+Brockfield Proteopedia - User contributions [en] 2026-09-21T18:09:33Z User contributions MediaWiki 1.43.8 https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317828 PhoP-PhoQ 2011-11-15T23:02:18Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia coli''[http://en.wikipedia.org/wiki/Escherichia_coli], ''Salmonella enterica'' Typhi[http://en.wikipedia.org/wiki/Salmonella_enterica], and ''Yersinia pestis''[http://en.wikipedia.org/wiki/Yersinia_pestis]. In a classic two component regulatory system, there exists a sensor kinase and a response regulator<ref name=Hoch>PMID:10745001</ref>. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<ref name=Hoch>PMID:10745001</ref><br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain.<ref name=Bachhawat>PMID:17545283</ref> At a conserved Asp residue (<scene name='PhoP-PhoQ/Asp51-bef3/1'>Asp51 in this case</scene>), the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position.<ref name=Bachhawat>PMID:17545283</ref>:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene><ref name=Bachhawat>PMID:17545283</ref>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Spontaneous Dimerization===<br /> <br /> ----<br /> <br /> Spontaneous dimerization of the unactivated phoP regulatory domain can be observed in vitro, but is likely due to high concentration of the protein and may not occur in vivo. Although the dimerization of the unactivated phoP regulatory domain results in a homodimer similar to the activated homodimer, it is significantly less stable. Activation by the phosphoryl group helps to stabilize the <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene> dimerization interphase. Without the phosphoryl group, the two monomers dimerize in an asymmetric fashion that lends to molecular instability.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<ref name=Angelichio>PMID:12438320</ref><br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<ref name=Hoch>PMID:10745001</ref><br /> <br /> A particular and well studied example of this is the role of [Mg<sup>2+</sup>] in ''Salmonella enterica'' Typhi virulence. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella enterica'' Typphi pathogenesis. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome.<br /> <br /> Two component regulatory systems such as phoP-phoQ are obviously an attractive target for future antimicrobial drugs. If the phoP-phoQ can be altered to a dysfunctional state, the relevant bacteria would have decreased pathogenicity and increased suceptibility to nonspecific immune defense.<br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> ===References===<br /> <br /> ----<br /> <br /> {{Reflist}}<br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317826 PhoP-PhoQ 2011-11-15T23:01:42Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia coli''[http://en.wikipedia.org/wiki/Escherichia_coli], ''Salmonella enterica'' Typhi[http://en.wikipedia.org/wiki/Salmonella_enterica], and ''Yersinia pestis''[http://en.wikipedia.org/wiki/Yersinia_pestis]. In a classic two component regulatory system, there exists a sensor kinase and a response regulator<ref name=Hoch>PMID:10745001</ref>. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<ref name=Hoch>PMID:10745001</ref><br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain.<ref name=Bachhawat>PMID:17545283</ref> At a conserved Asp residue (<scene name='PhoP-PhoQ/Asp51-bef3/1'>Asp51 in this case</scene>), the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position.<ref name=Bachhawat>PMID:17545283</ref>:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene><ref name=Bachhawat>PMID:17545283</ref>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Spontaneous Dimerization===<br /> <br /> ----<br /> <br /> Spontaneous dimerization of the unactivated phoP regulatory domain can be observed in vitro, but is likely due to high concentration of the protein and may not occur in vivo. Although the dimerization of the unactivated phoP regulatory domain results in a homodimer similar to the activated homodimer, it is significantly less stable. Activation by the phosphoryl group helps to stabilize the <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene> dimerization interphase. Without the phosphoryl group, the two monomers dimerize in an asymmetric fashion that lends to molecular instability.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<ref name=Angelichio>PMID:12438320</ref><br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<ref name=Hoch>PMID:10745001</ref><br /> <br /> A particular and well studied example of this is the role of [Mg<sup>2+</sup.] in ''Salmonella enterica'' Typhi virulence. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella enterica'' Typphi pathogenesis. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome.<br /> <br /> Two component regulatory systems such as phoP-phoQ are obviously an attractive target for future antimicrobial drugs. If the phoP-phoQ can be altered to a dysfunctional state, the relevant bacteria would have decreased pathogenicity and increased suceptibility to nonspecific immune defense.<br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> ===References===<br /> <br /> ----<br /> <br /> {{Reflist}}<br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317824 PhoP-PhoQ 2011-11-15T22:56:06Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia coli''[http://en.wikipedia.org/wiki/Escherichia_coli], ''Salmonella enterica''[http://en.wikipedia.org/wiki/Salmonella_enterica], and ''Yersinia pestis''[http://en.wikipedia.org/wiki/Yersinia_pestis]. In a classic two component regulatory system, there exists a sensor kinase and a response regulator<ref name=Hoch>PMID:10745001</ref>. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<ref name=Hoch>PMID:10745001</ref><br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain.<ref name=Bachhawat>PMID:17545283</ref> At a conserved Asp residue (<scene name='PhoP-PhoQ/Asp51-bef3/1'>Asp51 in this case</scene>), the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position.<ref name=Bachhawat>PMID:17545283</ref>:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene><ref name=Bachhawat>PMID:17545283</ref>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Spontaneous Dimerization===<br /> <br /> ----<br /> <br /> Spontaneous dimerization of the unactivated phoP regulatory domain can be observed in vitro, but is likely due to high concentration of the protein and may not occur in vivo. Although the dimerization of the unactivated phoP regulatory domain results in a homodimer similar to the activated homodimer, it is significantly less stable. Activation by the phosphoryl group helps to stabilize the <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene> dimerization interphase. Without the phosphoryl group, the two monomers dimerize in an asymmetric fashion that lends to molecular instability.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<ref name=Angelichio>PMID:12438320</ref><br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<ref name=Hoch>PMID:10745001</ref><br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome.<br /> <br /> Two component regulatory systems such as phoP-phoQ are obviously an attractive target for future antimicrobial drugs. If the phoP-phoQ can be altered to a dysfunctional state, the relevant bacteria would have decreased pathogenicity and increased suceptibility to nonspecific immune defense.<br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> ===References===<br /> <br /> ----<br /> <br /> {{Reflist}}<br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317822 PhoP-PhoQ 2011-11-15T22:50:22Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia coli''[http://en.wikipedia.org/wiki/Escherichia_coli], ''Salmonella enterica''[http://en.wikipedia.org/wiki/Salmonella_enterica], and ''Yersinia pestis''[http://en.wikipedia.org/wiki/Yersinia_pestis]. In a classic two component regulatory system, there exists a sensor kinase and a response regulator<ref name=Hoch>PMID:10745001</ref>. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<ref name=Hoch>PMID:10745001</ref><br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain.<ref name=Bachhawat>PMID:17545283</ref> At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position.<ref name=Bachhawat>PMID:17545283</ref>:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene><ref name=Bachhawat>PMID:17545283</ref>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Spontaneous Dimerization===<br /> <br /> ----<br /> <br /> Spontaneous dimerization of the unactivated phoP regulatory domain can be observed in vitro, but is likely due to high concentration of the protein and may not occur in vivo. Although the dimerization of the unactivated phoP regulatory domain results in a homodimer similar to the activated homodimer, it is significantly less stable. Activation by the phosphoryl group helps to stabilize the α-4 helix, β-5 sheet and α-5 helix dimerization interphase. Without the phosphoryl group, the two monomers dimerize in an asymmetric fashion that lends to molecular instability.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<ref name=Angelichio>PMID:12438320</ref><br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<ref name=Hoch>PMID:10745001</ref><br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome.<br /> <br /> Two component regulatory systems such as phoP-phoQ are obviously an attractive target for future antimicrobial drugs. If the phoP-phoQ can be altered to a dysfunctional state, the relevant bacteria would have decreased pathogenicity and increased suceptibility to nonspecific immune defense.<br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> ===References===<br /> <br /> ----<br /> <br /> {{Reflist}}<br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317821 PhoP-PhoQ 2011-11-15T22:46:37Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator<ref name=Hoch>PMID:10745001</ref>. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<ref name=Hoch>PMID:10745001</ref><br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain.<ref name=Bachhawat>PMID:17545283</ref> At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position.<ref name=Bachhawat>PMID:17545283</ref>:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene><ref name=Bachhawat>PMID:17545283</ref>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Spontaneous Dimerization===<br /> <br /> ----<br /> <br /> Spontaneous dimerization of the unactivated phoP regulatory domain can be observed in vitro, but is likely due to high concentration of the protein and may not occur in vivo. Although the dimerization of the unactivated phoP regulatory domain results in a homodimer similar to the activated homodimer, it is significantly less stable. Activation by the phosphoryl group helps to stabilize the α-4 helix, β-5 sheet and α-5 helix dimerization interphase. Without the phosphoryl group, the two monomers dimerize in an asymmetric fashion that lends to molecular instability.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<ref name=Angelichio>PMID:12438320</ref><br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<ref name=Hoch>PMID:10745001</ref><br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome.<br /> <br /> Two component regulatory systems such as phoP-phoQ are obviously an attractive target for future antimicrobial drugs. If the phoP-phoQ can be altered to a dysfunctional state, the relevant bacteria would have decreased pathogenicity and increased suceptibility to nonspecific immune defense.<br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> ===References===<br /> <br /> ----<br /> <br /> {{Reflist}}<br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317819 PhoP-PhoQ 2011-11-15T22:30:36Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator<ref name=Hoch>PMID:10745001</ref>. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<ref name=Hoch>PMID:10745001</ref><br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain.<ref name=Bachhawat>PMID:17545283</ref> At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position.<ref name=Bachhawat>PMID:17545283</ref>:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene><ref name=Bachhawat>PMID:17545283</ref>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<ref name=Bachhawat>PMID:17545283</ref><br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<ref name=Bachhawat>PMID:17545283</ref><br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<ref name=Angelichio>PMID:12438320</ref><br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<ref name=Hoch>PMID:10745001</ref><br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> ===References===<br /> <br /> ----<br /> <br /> {{Reflist}}<br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317813 PhoP-PhoQ 2011-11-15T22:19:33Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<ref name=Angelichio>PMID: PMC132940</ref><br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> {{Reflist}}<br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317805 PhoP-PhoQ 2011-11-15T21:57:25Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and modulates transcription.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> (T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/4'>Mg</scene><sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/2'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/2'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/3'>Gly53</scene>.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317796 PhoP-PhoQ 2011-11-15T20:27:37Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> :::::::(T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/2'>Mg</scene> <sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/1'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" <scene name='PhoP-PhoQ/Thr79-f2/1'>Thr79</scene>, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of <scene name='PhoP-PhoQ/Gly53-f2/1'>Gly53</scene>.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317793 PhoP-PhoQ 2011-11-15T20:14:19Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> :::::::(T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site <scene name='PhoP-PhoQ/Mg-f1/2'>Mg</scene> <sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/1'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" Thr79, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of Gly53.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317792 PhoP-PhoQ 2011-11-15T20:10:46Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> :::::::(T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site Mg<sup>2+</sup>. The conserved active site lysine, <scene name='PhoP-PhoQ/Lys101-f3/1'>Lys101</scene>, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" Thr79, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of Gly53.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317726 PhoP-PhoQ 2011-11-15T08:18:35Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> :::::::(T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, <scene name='Sandbox_Reserved_344/P-analog/1'>Beryllofluoride</scene> (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site Mg<sup>2+</sup>. The conserved active site lysine, Lys101, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. A conserved "switch residue" Thr79, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>. F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup> also forms a H-bond with the backbone nitrogen atom of Gly53.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317725 PhoP-PhoQ 2011-11-15T08:11:14Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> <br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> :::::::(T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by <scene name='Sandbox_Reserved_344/Dimerization_surface/1'>α-4 helix, β-5 sheet and α-5 helix face</scene>. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, Beryllofluoride (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site Mg<sup>2+</sup>. The conserved active site lysine, Lys101, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. Finally, a conserved "switch residue" Thr79, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317721 PhoP-PhoQ 2011-11-15T07:23:40Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as a low [Mg<sup>2+</sup>], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> {{TOC limit|limit=2}}<br /> <br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> E. coli phoP is a 223 residue protein containing a 120-residue regulatory domain joined by a 5-residue linker to a 98 residue c-terminal DNA binding effector domain. At a conserved Asp residue, the regulatory domain can be modified by a phosphoryl group from the protein kinase function of phoQ. Phosphorylation of the regulatory domain modulates the activity of the effector domain to bind DNA and regulate transcription. Phosphorylated, or "activated" phoP binds to "phoP boxes" on bacterial DNA, which consist of two direct hexanucleotide repeats separated by a five nucleotide spacer located at the -35 position:<br /> :::::::(T/G)GTTTA<br /> <br /> ===Dimerization of Activated phoP===<br /> <br /> ----<br /> <br /> The activated phoP regulatory domain dimerizes with two-fold symmetry using the face formed by helix &alpha 4, strand &beta 5, and helix &alpha 5. The phosphoryl group donated from phoQ is used to stabilize the active conformation by inducing dimerization. Due to the absence of an intramolecular domain interface which precludes direct transmission of an activation signal, this function as a dimerization motif seems to be the phosphoryl group's only role.<br /> <br /> ===Beryllofluoride Coordination===<br /> <br /> ----<br /> <br /> In this structure, Beryllofluoride (BeF<sub>3</sub><sup>-</sup>) is used as a phosphoryl analog to induce the active state conformation. There are numerous bonds that form as a result of BeF<sub>3</sub><sup>-</sup> coordination. F<sub>1</sub> of BeF<sub>3</sub><sup>-</sup> helps satisfy the octahedral coordination of a present active site Mg<sup>2+</sup>. The conserved active site lysine, Lys101, forms important intramolecular and intermolecular salt bridges, one of which is with F<sub>3</sub> of BeF<sub>3</sub><sup>-</sup>. Finally, a conserved "switch residue" Thr79, involved in the activation of all response regulators, forms a H-bond with F<sub>2</sub> of BeF<sub>3</sub><sup>-</sup>.<br /> </StructureSection><br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg<sup>2+</sup>]. In response to low [Mg<sup>2+</sup>], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317707 PhoP-PhoQ 2011-11-15T04:56:27Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as [Mg2+], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg2+]. In response to low [Mg2+], such as would be found inside a macrophage phagosome, phoQ autophosphorylates and transphorphorylates phoP. PhoP then binds to the bacterial DNA and simultaneously activates the expression of pags (phoP activated genes) and represses the expression of prgs (phoP repressed genes). Among the gene products of pags are proteins necessary to survive inside the macrophage, a critical stage of ''Salmonella Typhirium'' virulence. Among the gene products of prgs are proteins necessary for invasion and infection of the host, which are less important once in a host macrophage's phagosome. <br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> PhoP's role in the phoP-phoQ two component phosphorelay system...<br /> </StructureSection><br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317695 PhoP-PhoQ 2011-11-15T02:35:45Z

<p>Andrew Brockfield: /* Introduction */</p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as [Mg2+], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which in turn binds DNA and activates and represses specific genes.<br /> <br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg2+].<br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> PhoP's role in the phoP-phoQ two component phosphorelay system...<br /> </StructureSection><br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317694 PhoP-PhoQ 2011-11-15T02:34:30Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two component regulatory system found in some gram-negative bacteria such as ''Escherichia Coli'', ''Salmonella Typhimurium'', and ''Yersinia Pestis''. In a classic two component regulatory system, there exists a sensor kinase and a response regulator. In the phoP-phoQ system, phoQ acts as the sensor kinase and phoP acts as the response regulator. The purpose of this signal transduction system in bacteria is to modify cellular output in response to environmental signals. In response to particular environmental stimuli, such as [Mg2+], the sensor kinase, phoQ autophosphorylates. Phosphorylated phoQ then transphosphorylates the response regulator, phoP, which when phosphorylated binds DNA and activates and represses specific genes.<br /> <br /> ===PhoP-PhoQ and Virulence===<br /> <br /> ----<br /> <br /> Most known virulence factors have been isolated by designing laboratory conditions that presumably stimulate environmental signals present in host tissues. However, many pathogenic bacteria do not express their virulence factors until specific host signals are detected, signals which are near impossible to accurately reproduce in a laboratory. To overcome this, a new approach entitled IVET (in vivo expression technology) has been developed. IVET uses animal tissue as the selective medium to enrich bacterial virulence factors specifically induced during infection.<br /> <br /> Pathogenic bacteria seldom express virulence genes constitutively, they instead need to be able to express the correct virulence genes in the correct environment. Not all virulence factors confer a selective advantage to the microbe at the same stage of infection. Thus, it is the job of the phoP-phoQ system to modulate virulence gene expression according to the cellular micro-environment.<br /> <br /> A particular and well studied environmental factor relative to the phoP-phoQ system is [Mg2+].<br /> <StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> ===PhoP: The Response Regulator===<br /> <br /> ----<br /> PhoP's role in the phoP-phoQ two component phosphorelay system...<br /> </StructureSection><br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317692 PhoP-PhoQ 2011-11-15T01:41:39Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> {{TOC limit|limit=2}}<br /> <br /> <br /> ===Introduction===<br /> <br /> ----<br /> <br /> '''PhoP-PhoQ''' is a two-component system which governs virulence and mediates the adptation to Mg+2-limiting conditions. PhoP is a response regulator and PhoQ is the inner membrane sensor. See details on PhoP in [[PhoP Regulatory Domain]].<br /> <br /> ==PhoP==<StructureSection load='2pl1' size='500' side='right' caption='BeF activated PhoP domain of E. Coli (PDB entry [[2pl1]])' scene=''><br /> ===PhoP: A Response Regulator===<br /> <br /> ----<br /> PhoP's role in the phoP-phoQ two component phosphorelay system...<br /> </StructureSection><br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield https://proteopedia.org/index.php?title=PhoP-PhoQ&diff=1317690 PhoP-PhoQ 2011-11-15T01:27:15Z

<p>Andrew Brockfield: </p> <hr /> <div>{{STRUCTURE_3bq8| PDB=3bq8 | SIZE=400| SCENE= |right|CAPTION=''E. coli'' Se-Met PhoQ complex with Ni+2 and acetic acid, [[3bq8]] }}<br /> <br /> '''PhoP-PhoQ''' is a two-component system which governs virulence and mediates the adptation to Mg+2-limiting conditions. PhoP is a response regulator and PhoQ is the inner membrane sensor. See details on PhoP in [[PhoP Regulatory Domain]].<br /> <br /> {{TOC limit|limit=2}}<br /> <br /> <Structure load='2pl1' size='500' frame='true' align='right' caption='BeF activated PhoP domain in E. Coli' scene='Insert optional scene name here' /><br /> <br /> == 3D Structures of PhoP-PhoQ==<br /> <br /> ===PhoP===<br /> <br /> [[3r0j]] – MtPhoP – ''Mycobacterium tuberculosis''<br /><br /> [[2pmu]] – MtPhoP DNA-binding domain<br /><br /> [[2pkx]] – EcPhoP regulatory domain (mutant) – ''Escherichia coli''<br /><br /> [[2pl1]] - EcPhoP regulatory domain (mutant) + BeF3<br /><br /> [[1mvo]] – PhoP N terminal – ''Bacillus subtilis''<br /> <br /> ===PhoQ===<br /> <br /> [[3cgy]] – StPhoQ catalytic domain + radicicol – ''Salmonella typhimurium''<br /><br /> [[3cgz]] - StPhoQ catalytic domain<br /><br /> [[1yax]] - StPhoQ sensor domain (mutant)<br /><br /> [[3bq8]] – EcPhoQ<br /><br /> [[3bqa]] – EcPhoQ (mutant)<br /><br /> [[1id0]] – EcPhoQ kinase domain<br /> <br /> <br /> [[Category:Topic Page]]</div>

Andrew Brockfield