3fip
Crystal structure of Usher PapC translocation poreCrystal structure of Usher PapC translocation pore
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 PubMedUshers constitute a family of bacterial outer membrane proteins responsible for the assembly and secretion of surface organelles such as the pilus. The structure at 3.15-A resolution of the usher pyelonephritis-associated pili C (PapC) translocation domain reveals a 24-stranded kidney-shaped beta-barrel, occluded by an internal plug domain. The dimension of the pore allows tandem passage of individual folded pilus subunits in an upright pilus growth orientation, but is insufficient for accommodating donor strand exchange. The molecular packing revealed by the crystal structure shows that 2 PapC molecules in head-to-head orientation interact via exposed beta-strand edges, which could be the preferred dimer interaction in solution. In vitro reconstitution of fiber assemblies suggest that PapC monomers may be sufficient for fiber assembly and secretion; both the plug domain and the C-terminal domain of PapC are required for filament assembly, whereas the N-terminal domain is mainly responsible for recruiting the chaperone-subunit complexes to the usher. The plug domain has a dual function: gating the beta-pore and participating in pilus assembly. Insights into pilus assembly and secretion from the structure and functional characterization of usher PapC.,Huang Y, Smith BS, Chen LX, Baxter RH, Deisenhofer J Proc Natl Acad Sci U S A. 2009 May 5;106(18):7403-7. Epub 2009 Apr 20. PMID:19380723[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References |
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