2a69: Difference between revisions

Line 1:

[[Image:2a69.gif|left|200px]]<br /><applet load="2a69" size="~~450~~" color="white" frame="true" align="right" spinBox="true"

[[Image:2a69.gif|left|200px]]<br /><applet load="2a69" size="350" color="white" frame="true" align="right" spinBox="true"

caption="2a69, resolution 2.50Å" />

'''Crystal structure of the T. Thermophilus RNA polymerase holoenzyme in complex with antibiotic rifapentin'''<br />

==Overview==

Rifamycins, the clinically important antibiotics, target bacterial RNA, polymerase (RNAP). A proposed mechanism in which rifamycins sterically, block the extension of nascent RNA beyond three nucleotides does not alone, explain why certain RNAP mutations confer resistance to some but not other, rifamycins. Here we show that unlike rifampicin and rifapentin, and, contradictory to the steric model, rifabutin inhibits formation of the, first and second phosphodiester bonds. We report 2.5 A resolution, structures of rifabutin and rifapentin complexed with the Thermus, thermophilus RNAP holoenzyme. The structures reveal functionally important, distinct interactions of antibiotics with the initiation sigma factor., Strikingly, both complexes lack the catalytic Mg2+ ion observed in the, apo-holoenzyme, whereas an increase in Mg2+ concentration confers, resistance to rifamycins. We propose that a rifamycin-induced signal is, transmitted over approximately 19 A to the RNAP active site to slow down, catalysis. Based on structural predictions, we designed enzyme, substitutions that apparently interrupt this allosteric signal.

Rifamycins, the clinically important antibiotics, target bacterial RNA polymerase (RNAP). A proposed mechanism in which rifamycins sterically block the extension of nascent RNA beyond three nucleotides does not alone explain why certain RNAP mutations confer resistance to some but not other rifamycins. Here we show that unlike rifampicin and rifapentin, and contradictory to the steric model, rifabutin inhibits formation of the first and second phosphodiester bonds. We report 2.5 A resolution structures of rifabutin and rifapentin complexed with the Thermus thermophilus RNAP holoenzyme. The structures reveal functionally important distinct interactions of antibiotics with the initiation sigma factor. Strikingly, both complexes lack the catalytic Mg2+ ion observed in the apo-holoenzyme, whereas an increase in Mg2+ concentration confers resistance to rifamycins. We propose that a rifamycin-induced signal is transmitted over approximately 19 A to the RNAP active site to slow down catalysis. Based on structural predictions, we designed enzyme substitutions that apparently interrupt this allosteric signal.

==About this Structure==

2A69 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with RPT, ZN and MG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_RNA_polymerase DNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.6 2.7.7.6] Full crystallographic information is available from [http://~~ispc~~.weizmann.ac.il/oca-bin/ocashort?id=2A69 OCA].

2A69 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with <scene name='pdbligand=RPT:'>RPT</scene>, <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_RNA_polymerase DNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.6 2.7.7.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A69 OCA].

==Reference==

Line 18:

[[Category: Matsugaki, N.]]

[[Category: Perederina, A.]]

[[Category: RSGI, RIKEN.Structural.Genomics/Proteomics.Initiative.]]

[[Category: RSGI, RIKEN Structural Genomics/Proteomics Initiative.]]

[[Category: Svetlov, D.]]

[[Category: Svetlov, V.]]

[[Category: Tahirov, T.H.]]

[[Category: Tahirov, T H.]]

[[Category: Vassylyev, D.G.]]

[[Category: Vassylyev, D G.]]

[[Category: Vassylyeva, M.N.]]

[[Category: Vassylyeva, M N.]]

[[Category: Wakatsuki, S.]]

[[Category: MG]]

Line 36:

[[Category: transcription regulation]]

''Page seeded by [http://~~ispc~~.weizmann.ac.il/oca OCA ] on ~~Wed Nov~~ 21 07:56:~~24 2007~~''

''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:23:59 2008''

Navigation menu

Page actions

Page actions

Personal tools

Navigation

Search

Tools

@@ Line 1: / Line 1: @@
-[[Image:2a69.gif|left|200px]]<br /><applet load="2a69" size="450" color="white" frame="true" align="right" spinBox="true"
+[[Image:2a69.gif|left|200px]]<br /><applet load="2a69" size="350" color="white" frame="true" align="right" spinBox="true"
 caption="2a69, resolution 2.50&Aring;" />
 '''Crystal structure of the T. Thermophilus RNA polymerase holoenzyme in complex with antibiotic rifapentin'''<br />
 ==Overview==
-Rifamycins, the clinically important antibiotics, target bacterial RNA, polymerase (RNAP). A proposed mechanism in which rifamycins sterically, block the extension of nascent RNA beyond three nucleotides does not alone, explain why certain RNAP mutations confer resistance to some but not other, rifamycins. Here we show that unlike rifampicin and rifapentin, and, contradictory to the steric model, rifabutin inhibits formation of the, first and second phosphodiester bonds. We report 2.5 A resolution, structures of rifabutin and rifapentin complexed with the Thermus, thermophilus RNAP holoenzyme. The structures reveal functionally important, distinct interactions of antibiotics with the initiation sigma factor., Strikingly, both complexes lack the catalytic Mg2+ ion observed in the, apo-holoenzyme, whereas an increase in Mg2+ concentration confers, resistance to rifamycins. We propose that a rifamycin-induced signal is, transmitted over approximately 19 A to the RNAP active site to slow down, catalysis. Based on structural predictions, we designed enzyme, substitutions that apparently interrupt this allosteric signal.
+Rifamycins, the clinically important antibiotics, target bacterial RNA polymerase (RNAP). A proposed mechanism in which rifamycins sterically block the extension of nascent RNA beyond three nucleotides does not alone explain why certain RNAP mutations confer resistance to some but not other rifamycins. Here we show that unlike rifampicin and rifapentin, and contradictory to the steric model, rifabutin inhibits formation of the first and second phosphodiester bonds. We report 2.5 A resolution structures of rifabutin and rifapentin complexed with the Thermus thermophilus RNAP holoenzyme. The structures reveal functionally important distinct interactions of antibiotics with the initiation sigma factor. Strikingly, both complexes lack the catalytic Mg2+ ion observed in the apo-holoenzyme, whereas an increase in Mg2+ concentration confers resistance to rifamycins. We propose that a rifamycin-induced signal is transmitted over approximately 19 A to the RNAP active site to slow down catalysis. Based on structural predictions, we designed enzyme substitutions that apparently interrupt this allosteric signal.
 ==About this Structure==
-A69 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with RPT, ZN and MG as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_RNA_polymerase DNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.6 2.7.7.6] Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2A69 OCA].
+A69 is a [http://en.wikipedia.org/wiki/Protein_complex Protein complex] structure of sequences from [http://en.wikipedia.org/wiki/Thermus_thermophilus Thermus thermophilus] with <scene name='pdbligand=RPT:'>RPT</scene>, <scene name='pdbligand=ZN:'>ZN</scene> and <scene name='pdbligand=MG:'>MG</scene> as [http://en.wikipedia.org/wiki/ligands ligands]. Active as [http://en.wikipedia.org/wiki/DNA-directed_RNA_polymerase DNA-directed RNA polymerase], with EC number [http://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.7.7.6 2.7.7.6] Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2A69 OCA].
 ==Reference==
@@ Line 18: / Line 18: @@
 [[Category: Matsugaki, N.]]
 [[Category: Perederina, A.]]
-[[Category: RSGI, RIKEN.Structural.Genomics/Proteomics.Initiative.]]
+[[Category: RSGI, RIKEN Structural Genomics/Proteomics Initiative.]]
 [[Category: Svetlov, D.]]
 [[Category: Svetlov, V.]]
-[[Category: Tahirov, T.H.]]
+[[Category: Tahirov, T H.]]
-[[Category: Vassylyev, D.G.]]
+[[Category: Vassylyev, D G.]]
-[[Category: Vassylyeva, M.N.]]
+[[Category: Vassylyeva, M N.]]
 [[Category: Wakatsuki, S.]]
 [[Category: MG]]
@@ Line 36: / Line 36: @@
 [[Category: transcription regulation]]
-''Page seeded by [http://ispc.weizmann.ac.il/oca OCA ] on Wed Nov 21 07:56:24 2007''
+''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:23:59 2008''