G3p: Difference between revisions
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===D2 Domain=== | ===D2 Domain=== | ||
{{STRUCTURE_2g3p | PDB=2g3p | SCENE= }} | |||
This domain contains eight beta strands: six in a mixed beta sheet and two interacting with D1 antiparallel sheet (β6 and β13 <ref name="lubkowski"/>. The amino acids between β6 and β7 doesn’t have a specific motif but has stabilizing hydrophobic interactions with other parts of the domain <ref name="lubkowski"/>. Three hairpins exist in this domain: between β8 and β9, β9 and β10, and β10 and β11 (cis proline in the last hairpin) <ref name="lubkowski"/>. The final secondary structural element is an alpha helix that interacts with rest of the domain via hydrophobic interactions <ref name="lubkowski"/>. Of note, there is a cation-π interaction between His 191 and Phe 199. The C terminus of D2 has seven peptides, 3 of which are proline, 1 of which is <scene name='G3p/Pro_213_in_cis_conformation/1'>in the cis conformation</scene> <ref name="lubkowski"/>. | This domain contains eight beta strands: six in a mixed beta sheet and two interacting with D1 antiparallel sheet (β6 and β13 <ref name="lubkowski"/>. The amino acids between β6 and β7 doesn’t have a specific motif but has stabilizing hydrophobic interactions with other parts of the domain <ref name="lubkowski"/>. Three hairpins exist in this domain: between β8 and β9, β9 and β10, and β10 and β11 (cis proline in the last hairpin) <ref name="lubkowski"/>. The final secondary structural element is an alpha helix that interacts with rest of the domain via hydrophobic interactions <ref name="lubkowski"/>. Of note, there is a cation-π interaction between His 191 and Phe 199. The C terminus of D2 has seven peptides, 3 of which are proline, 1 of which is <scene name='G3p/Pro_213_in_cis_conformation/1'>in the cis conformation</scene> <ref name="lubkowski"/>. | ||
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==Functional Implications== | ==Functional Implications== | ||
===Infectivity=== | ===Infectivity=== | ||
The function of the protein has a close correlation with its structural domains. The D1 domain interacts with TolA protein in the periplasm of the bacterial cell. <ref name="lubkowski"/><ref name="cabilly"/><ref name="holliger 99"/>. (The C terminal domain of TolA is the coreceptor for filamentous phage infection of E coli(Cell 90, 351-360 (1997)). The D2 domain binds to F pilus on the outer membrane of ''Escherichia coli'', however, it is also blocks TolA binding to D1 in the absence of the F pilus <ref name="chatellier"> PMID:10606756 </ref>. In fact, without the D2 domain, infectivity is very low<ref name="lubkowski"/>. It has been speculated that D2 interacts with the F pilus first, drawing the phage closer to the bacterial cell, thus allowing D1-TolA interactions to occur<ref name="holliger 99"/>. Chatellier et al suggest that the complex formed by D1 and D2 may prevent destruction of the protein from bacterial proteases, and upon binding the protein opens up and D3 can then reach the inner membrane of the bacteria<ref name="chatellier"/>. Lubkowski et al like the interaction between D1 and D2 to a horseshoe shaped molecule attributing hydrophobic molecules facing toward the center as stabilizing factors <ref name="lubkowski"/>. | The function of the protein has a close correlation with its structural domains. The D1 domain interacts with TolA protein in the periplasm of the bacterial cell. <ref name="lubkowski"/><ref name="cabilly"/><ref name="holliger 99"/>. (The C terminal domain of TolA is the coreceptor for filamentous phage infection of E coli(Cell 90, 351-360 (1997)). The D2 domain binds to F pilus on the outer membrane of ''Escherichia coli'', however, it is also blocks TolA binding to D1 in the absence of the F pilus <ref name="chatellier"> PMID:10606756 </ref>. In fact, without the D2 domain, infectivity is very low<ref name="lubkowski"/>. It has been speculated that D2 interacts with the F pilus first, drawing the phage closer to the bacterial cell, thus allowing D1-TolA interactions to occur<ref name="holliger 99"/>. Chatellier et al suggest that the complex formed by D1 and D2 may prevent destruction of the protein from bacterial proteases, and upon binding the protein opens up and D3 can then reach the inner membrane of the bacteria<ref name="chatellier"/>. Lubkowski et al like the interaction between D1 and D2 to a horseshoe shaped molecule attributing hydrophobic molecules facing toward the center as stabilizing factors <ref name="lubkowski"/>. | ||
{{STRUCTURE_1tol | PDB=1tol | SCENE= }} | |||
The function of D3 was elicited last. D3 domain “anchors” to F pilus (Chatellier et al) and is necessary for phage packaging (Holliger et al) | The function of D3 was elicited last. D3 domain “anchors” to F pilus (Chatellier et al) and is necessary for phage packaging (Holliger et al) | ||
Infection with filamentous phage does not cause host cell lysis or death (Gailus and Rasched). | Infection with filamentous phage does not cause host cell lysis or death (Gailus and Rasched). | ||
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===Phage Display=== | ===Phage Display=== | ||
N terminus can be truncated and the peptide of choice can be inserted (Cabilly) | N terminus can be truncated and the peptide of choice can be inserted (Cabilly) | ||
Insertions can also be done between D2 and D3 (H and R, 9032075) | Insertions can also be done between D2 and D3 (H and R, 9032075) | ||
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[[http://dx.doi.org/10.2210/pdb1s62/pdb 1s62]] | [[http://dx.doi.org/10.2210/pdb1s62/pdb 1s62]] | ||
==References== | ==References== | ||
<references/> | <references/> | ||
