3f65
The F4 fimbrial chaperone FaeE does not self-cap its interactive surfaces
Structural highlights
FunctionFAEE_ECOLX Mediates assembly of pili by forming soluble multimeric complexes with pili subunits as an intermediate step in the assembly process. This protein is involved in K88 pili assembly. Protects pilin protein from proteolytic degradation by DegP and from premature polymerization. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedMany Gram-negative bacteria use the chaperone-usher pathway to express adhesive surface structures, such as fimbriae, in order to mediate attachment to host cells. Periplasmic chaperones are required to shuttle fimbrial subunits or pilins through the periplasmic space in an assembly-competent form. The chaperones cap the hydrophobic surface of the pilins through a donor-strand complementation mechanism. FaeE is the periplasmic chaperone required for the assembly of the F4 fimbriae of enterotoxigenic Escherichia coli. The FaeE crystal structure shows a dimer formed by interaction between the pilin-binding interfaces of the two monomers. Dimerization and tetramerization have been observed previously in crystal structures of fimbrial chaperones and have been suggested to serve as a self-capping mechanism that protects the pilin-interactive surfaces in solution in the absence of the pilins. However, thermodynamic and biochemical data show that FaeE occurs as a stable monomer in solution. Other lines of evidence indicate that self-capping of the pilin-interactive interfaces is not a mechanism that is conservedly applied by all periplasmic chaperones, but is rather a case-specific solution to cap aggregation-prone surfaces. The F4 fimbrial chaperone FaeE is stable as a monomer that does not require self-capping of its pilin-interactive surfaces.,Van Molle I, Moonens K, Buts L, Garcia-Pino A, Panjikar S, Wyns L, De Greve H, Bouckaert J Acta Crystallogr D Biol Crystallogr. 2009 May;65(Pt 5):411-20. Epub 2009, Apr 18. PMID:19390146[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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