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==The crystal structure of CofB, the minor pilin subunit of CFA/III from human enterotoxigenic Escherichia coli.==
<StructureSection load='5ax6' size='340' side='right'caption='[[5ax6]], [[Resolution|resolution]] 1.88&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[5ax6]] is a 1 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=5AX6 OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=5AX6 FirstGlance]. <br>
</td></tr><tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=ACT:ACETATE+ION'>ACT</scene></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=5ax6 FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=5ax6 OCA], [https://pdbe.org/5ax6 PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=5ax6 RCSB], [https://www.ebi.ac.uk/pdbsum/5ax6 PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=5ax6 ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/Q93I73_ECOLX Q93I73_ECOLX] 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
In gram-negative bacteria, the assembly of type IV pilus (T4P) and the evolutionally related pseudopilus of type II secretion system involves specialized structural proteins called pilins and pseudopilins, respectively, and is dynamically regulated to promote bacterial pathogenesis. Previous studies have suggested that a structural "tip"-like hetero-complex formed through the interaction of at least three minor (pseudo) pilins plays an important role in this process, while some members of the pathogenic type IVb subfamily are known to have only one such minor pilin subunit whose function is still unknown. Here, we determined the crystal structure of the type IVb minor pilin CofB of colonization factor antigen/III from human enterotoxigenic Escherichia coli at 1.88-A resolution. The crystal structure, in conjunction with physicochemical analysis in solution, reveals a symmetrical homo-trimeric arrangement distinct from the hetero-complexes of minor (pseudo) pilins observed in other T4P and type II secretion systems. Each CofB monomer adopts a unique three-domain architecture, in which the C-terminal beta-sheet-rich lectin domain can effectively initiate trimer association of its pilin-like N-terminal domain through extensive hydrophobic interactions followed by domain swapping at the central hinge-like domain. Deletion of cofB produces a phenotype with no detectable pili formation on the cell surface, while molecular modeling indicates that the characteristic homo-trimeric structure of CofB is well situated at the pilus tip of colonization factor antigen/III formed by the major pilin CofA, suggesting a role for the minor pilin in the efficient initiation of T4P assembly.

Homo-trimeric Structure of the Type IVb Minor Pilin CofB Suggests Mechanism of CFA/III Pilus Assembly in Human Enterotoxigenic Escherichia coli.,Kawahara K, Oki H, Fukakusa S, Yoshida T, Imai T, Maruno T, Kobayashi Y, Motooka D, Iida T, Ohkubo T, Nakamura S J Mol Biol. 2016 Feb 11. pii: S0022-2836(16)00108-X. doi:, 10.1016/j.jmb.2016.02.003. PMID:26876601<ref>PMID:26876601</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 5ax6" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Escherichia coli]]
[[Category: Large Structures]]
[[Category: Daisuke M]]
[[Category: Fukaksua F]]
[[Category: Honda T]]
[[Category: Iida T]]
[[Category: Kawahara K]]
[[Category: Kobayashi Y]]
[[Category: Maruno T]]
[[Category: Nakamura S]]
[[Category: Ohkubo T]]
[[Category: Oki K]]
[[Category: Taniguchi T]]