Structural highlights
Function
[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. [PAPH_ECOLX] Fimbriae (also called pili), polar filaments radiating from the surface of the bacterium to a length of 0.5-1.5 micrometers and numbering 100-300 per cell, enable bacteria to colonize the epithelium of specific host organs. PapH seems to anchor the pilus to the bacterial cell. In addition the stoichiometric relationship between PapH and PapA determines the pilus length.
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 PubMed
P pili are important adhesive fibres that are assembled by the conserved chaperone-usher pathway. During pilus assembly, the subunits are incorporated into the growing fibre by the donor-strand exchange mechanism, whereby the beta-strand of the chaperone, which complements the incomplete immunoglobulin fold of each subunit, is displaced by the amino-terminal extension of an incoming subunit in a zip-in-zip-out exchange process that is initiated at the P5 pocket, an exposed hydrophobic pocket in the groove of the subunit. In vivo, termination of P pilus growth requires a specialized subunit, PapH. Here, we show that PapH is incorporated at the base of the growing pilus, where it is unable to undergo donor-strand exchange. This inability is not due to a stronger PapD-PapH interaction, but to a lack of a P5 initiator pocket in the PapH structure, suggesting that PapH terminates pilus growth because it is lacking the initiation point by which donor-strand exchange proceeds.
Molecular mechanism of P pilus termination in uropathogenic Escherichia coli.,Verger D, Miller E, Remaut H, Waksman G, Hultgren S EMBO Rep. 2006 Dec;7(12):1228-32. Epub 2006 Nov 3. PMID:17082819[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
See Also
References
- ↑ Verger D, Miller E, Remaut H, Waksman G, Hultgren S. Molecular mechanism of P pilus termination in uropathogenic Escherichia coli. EMBO Rep. 2006 Dec;7(12):1228-32. Epub 2006 Nov 3. PMID:17082819
