View source for 1qpx


==CRYSTAL STRUCTURES OF SELF-CAPPING PAPD CHAPERONE HOMODIMERS==
<StructureSection load='1qpx' size='340' side='right'caption='[[1qpx]], [[Resolution|resolution]] 2.40&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[1qpx]] is a 2 chain structure with sequence from [https://en.wikipedia.org/wiki/Escherichia_coli Escherichia coli]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=1QPX OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=1QPX 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]] 2.4&#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=1qpx FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=1qpx OCA], [https://pdbe.org/1qpx PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=1qpx RCSB], [https://www.ebi.ac.uk/pdbsum/1qpx PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=1qpx ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/PAPD_ECOLX PAPD_ECOLX] Binds and caps interactive surfaces on pilus subunits to prevent them from participating in non-productive interactions. Facilitates the import of subunits into the periplasm. May facilitate subunit folding. Chaperone-subunit complexes are then targeted to the PapC outer membrane usher where the chaperone must uncap from the subunits.
== 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/qp/1qpx_consurf.spt"</scriptWhenChecked>
    <scriptWhenUnchecked>script /wiki/extensions/Proteopedia/spt/initialview03.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=1qpx ConSurf].
<div style="clear:both"></div>
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
PapD is an immunoglobulin-like chaperone that mediates the assembly of P pili in uropathogenic strains of Escherichia coli. It binds and caps interactive surfaces on pilus subunits to prevent their premature associations in the periplasm. We elucidated the structural basis of a mechanism whereby PapD also interacts with itself, capping its own subunit binding surface. Crystal structures of dimeric forms of PapD revealed that this self-capping mechanism involves a rearrangement and ordering of the C2-D2 and F1-G1 loops upon dimerization which might ensure that a stable dimer is not formed in solution in spite of a relatively large dimer interface. An analysis of site directed mutations revealed that chaperone dimerization requires the same surface that is otherwise used to bind subunits.

Structural basis of chaperone self-capping in P pilus biogenesis.,Hung DL, Pinkner JS, Knight SD, Hultgren SJ Proc Natl Acad Sci U S A. 1999 Jul 6;96(14):8178-83. PMID:10393968<ref>PMID:10393968</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 1qpx" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Hultgren SJ]]
[[Category: Hung DL]]
[[Category: Knight SD]]
[[Category: Pinkner JS]]