View source for 2os7


==Caf1M periplasmic chaperone tetramer==
<StructureSection load='2os7' size='340' side='right'caption='[[2os7]], [[Resolution|resolution]] 2.90&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[2os7]] is a 6 chain structure with sequence from [https://en.wikipedia.org/wiki/Yersinia_pestis Yersinia pestis]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=2OS7 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=2OS7 FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">X-ray diffraction, [[Resolution|Resolution]] 2.9&#8491;</td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=2os7 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=2os7 OCA], [https://pdbe.org/2os7 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=2os7 RCSB], [https://www.ebi.ac.uk/pdbsum/2os7 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=2os7 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CAF1M_YERPE CAF1M_YERPE] Has a stimulatory role for the envelope antigen F1 secretion. It seems to interact with the subunit polypeptide and to prevent it from digestion by a protease.
== Evolutionary Conservation ==
[[Image:Consurf_key_small.gif|200px|right]]
Check<jmol>
  <jmolCheckbox>
    <scriptWhenChecked>; select protein; define ~consurf_to_do selected; consurf_initial_scene = true; script "/wiki/ConSurf/os/2os7_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview01.spt</scriptWhenUnchecked>
    <text>to colour the structure by Evolutionary Conservation</text>
  </jmolCheckbox>
</jmol>, as determined by [http://consurfdb.tau.ac.il/ ConSurfDB]. You may read the [[Conservation%2C_Evolutionary|explanation]] of the method and the full data available from [http://bental.tau.ac.il/new_ConSurfDB/main_output.php?pdb_ID=2os7 ConSurf].
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== Publication Abstract from PubMed ==
The chaperone Caf1M belongs to a family of ATP-independent periplasmic chaperones that together with outer membrane ushers assemble and secrete filamentous adhesion organelles in Gram-negative pathogens. It assists in folding and transport of Caf1 subunits of the F1 capsular antigen of Yersinia pestis, the microbe causing bubonic plague. In the periplasm, Caf1M prevents subunit aggregation by capping the extensive hydrophobic surface of activated Caf1. We found that subunit-free Caf1M exists predominantly as a tetramer [K(d) = (2-30) x 10(-14) M(3) in the 12-37 degrees C interval]. A 2.9 A resolution crystal structure of the Caf1M tetramer reveals that each of the four molecules contribute its subunit binding sequences (the A(1) and G(1) strands) to form an eight-stranded hetero-sandwich with a well-packed phenylalanine-rich hydrophobic core. Tetramerization protects chaperone molecules against enzymatic proteolysis. Deletions in the subunit binding motifs completely abolish tetramer assembly, suggesting that the hetero-sandwich is the main structural feature holding the tetramer together. Arresting tetramer assembly by a deletion of the N-terminal binding motif, while leaving the major subunit binding motif VGVFVQFAI (G(1) strand) intact, results in accumulation of unspecific aggregates. Deletions in the VGVFVQFAI motif abolish both tetramer assembly and aggregation, consistent with the predicted high beta-aggregation propensity for this motif. These results suggest that the packing of the aggregation-prone subunit binding sequences into the hetero-domain is a novel molecular mechanism preventing unspecific aggregation of the free chaperone.

A novel self-capping mechanism controls aggregation of periplasmic chaperone Caf1M.,Zavialov AV, Knight SD Mol Microbiol. 2007 Apr;64(1):153-64. PMID:17376079<ref>PMID:17376079</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
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== References ==
<references/>
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</StructureSection>
[[Category: Large Structures]]
[[Category: Yersinia pestis]]
[[Category: Knight SD]]
[[Category: Zavialov AZ]]