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Publication Abstract from PubMed

Type IV pilus-like systems are protein complexes that polymerize pilin fibres. They are critical for virulence in many bacterial pathogens. Pilin polymerization and depolymerization are powered by motor ATPases of the PilT/VirB11-like family. This family is thought to operate with C2 symmetry; however, most of these ATPases crystallize with either C3 or C6 symmetric conformations. The relevance of these conformations is unclear. Here, we determine the X-ray structures of PilT in four unique conformations and use these structures to classify the conformation of available PilT/VirB11-like family member structures. Single particle electron cryomicroscopy (cryoEM) structures of PilT reveal condition-dependent preferences for C2, C3, and C6 conformations. The physiologic importance of these conformations is validated by coevolution analysis and functional studies of point mutants, identifying a rare gain-of-function mutation that favours the C2 conformation. With these data, we propose a comprehensive model of PilT function with broad implications for PilT/VirB11-like family members.

Multiple conformations facilitate PilT function in the type IV pilus.,McCallum M, Benlekbir S, Nguyen S, Tammam S, Rubinstein JL, Burrows LL, Howell PL Nat Commun. 2019 Nov 15;10(1):5198. doi: 10.1038/s41467-019-13070-z. PMID:31729381^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.