Structural highlights
Function
[PAPC_ECOLX] Involved in the export and assembly of pili subunits across the outer membrane. Forms a hexameric ring-shaped pore in the outer bacterial membrane. The 2 nanometer-diameter pore allows the passage of the thin tip fibrillum. As for the rod, it probably unwinds into linear fibers which would therefore be narrow enough to pass through the pore.
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
Gram-negative pathogens commonly exhibit adhesive pili on their surfaces that mediate specific attachment to the host. A major class of pili is assembled via the chaperone/usher pathway. Here, the structural basis for pilus fiber assembly and secretion performed by the outer membrane assembly platform--the usher--is revealed by the crystal structure of the translocation domain of the P pilus usher PapC and single particle cryo-electron microscopy imaging of the FimD usher bound to a translocating type 1 pilus assembly intermediate. These structures provide molecular snapshots of a twinned-pore translocation machinery in action. Unexpectedly, only one pore is used for secretion, while both usher protomers are used for chaperone-subunit complex recruitment. The translocating pore itself comprises 24 beta strands and is occluded by a folded plug domain, likely gated by a conformationally constrained beta-hairpin. These structures capture the secretion of a virulence factor across the outer membrane of gram-negative bacteria.
Fiber formation across the bacterial outer membrane by the chaperone/usher pathway.,Remaut H, Tang C, Henderson NS, Pinkner JS, Wang T, Hultgren SJ, Thanassi DG, Waksman G, Li H Cell. 2008 May 16;133(4):640-52. PMID:18485872[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Remaut H, Tang C, Henderson NS, Pinkner JS, Wang T, Hultgren SJ, Thanassi DG, Waksman G, Li H. Fiber formation across the bacterial outer membrane by the chaperone/usher pathway. Cell. 2008 May 16;133(4):640-52. PMID:18485872 doi:10.1016/j.cell.2008.03.033
