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Structure of the bacterial sex F pilus (13.2 Angstrom rise)
Structural highlights
FunctionPIL1_ECOLI Propilin is the precursor of the pilus subunit, pilin, that forms conjugative pili, the filamentous surface appendages required for cell-to-cell contact during the earlier stages of bacterial conjugation, and that retract after contact is established. Mature pilin is assembled with the help of TraQ and TraX (PubMed:1464628, PubMed:6090426). Functions as a receptor for CdiA-CT from E.cloacae and E.coli, although it is not clear if this is physiologically relevant (PubMed:24889811).[1] [2] [3] Publication Abstract from PubMedConjugative pili are widespread bacterial appendages that play important roles in horizontal gene transfer, in spread of antibiotic resistance genes, and as sites of phage attachment. Among conjugative pili, the F "sex" pilus encoded by the F plasmid is the best functionally characterized, and it is also historically the most important, as the discovery of F-plasmid-mediated conjugation ushered in the era of molecular biology and genetics. Yet, its structure is unknown. Here, we present atomic models of two F family pili, the F and pED208 pili, generated from cryoelectron microscopy reconstructions at 5.0 and 3.6 A resolution, respectively. These structures reveal that conjugative pili are assemblies of stoichiometric protein-phospholipid units. We further demonstrate that each pilus type binds preferentially to particular phospholipids. These structures provide the molecular basis for F pilus assembly and also shed light on the remarkable properties of conjugative pili in bacterial secretion and phage infection. Structure of the Bacterial Sex F Pilus Reveals an Assembly of a Stoichiometric Protein-Phospholipid Complex.,Costa TR, Ilangovan A, Ukleja M, Redzej A, Santini JM, Smith TK, Egelman EH, Waksman G Cell. 2016 Sep 8;166(6):1436-1444.e10. doi: 10.1016/j.cell.2016.08.025. PMID:27610568[4] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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