6e15

Handover mechanism of the growing pilus by the bacterial outer membrane usher FimDHandover mechanism of the growing pilus by the bacterial outer membrane usher FimD

6e15, resolution 5.10Å Show:Asymmetric Unit Biological Assembly Structural highlights 6e15 is a 5 chain structure with sequence from Escherichia coli. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: Electron Microscopy, Resolution 5.1Å Experimental data: Check Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function FIMC_ECOLI Required for the biogenesis of type 1 fimbriae. Binds and interact with FimH. Publication Abstract from PubMed Pathogenic bacteria such as Escherichia coli assemble surface structures termed pili, or fimbriae, to mediate binding to host-cell receptors(1). Type 1 pili are assembled via the conserved chaperone-usher pathway(2-5). The outer-membrane usher FimD recruits pilus subunits bound by the chaperone FimC via the periplasmic N-terminal domain of the usher. Subunit translocation through the beta-barrel channel of the usher occurs at the two C-terminal domains (which we label CTD1 and CTD2) of this protein. How the chaperone-subunit complex bound to the N-terminal domain is handed over to the C-terminal domains, as well as the timing of subunit polymerization into the growing pilus, have previously been unclear. Here we use cryo-electron microscopy to capture a pilus assembly intermediate (FimD-FimC-FimF-FimG-FimH) in a conformation in which FimD is in the process of handing over the chaperone-bound end of the growing pilus to the C-terminal domains. In this structure, FimF has already polymerized with FimG, and the N-terminal domain of FimD swings over to bind CTD2; the N-terminal domain maintains contact with FimC-FimF, while at the same time permitting access to the C-terminal domains. FimD has an intrinsically disordered N-terminal tail that precedes the N-terminal domain. This N-terminal tail folds into a helical motif upon recruiting the FimC-subunit complex, but reorganizes into a loop to bind CTD2 during handover. Because both the N-terminal and C-terminal domains of FimD are bound to the end of the growing pilus, the structure further suggests a mechanism for stabilizing the assembly intermediate to prevent the pilus fibre diffusing away during the incorporation of thousands of subunits. Handover mechanism of the growing pilus by the bacterial outer-membrane usher FimD.,Du M, Yuan Z, Yu H, Henderson N, Sarowar S, Zhao G, Werneburg GT, Thanassi DG, Li H Nature. 2018 Oct 3. pii: 10.1038/s41586-018-0587-z. doi:, 10.1038/s41586-018-0587-z. PMID:30283140 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Adhesin 3D structures