PDBsum entry 6olm

Motor protein

PDB id: 6olm

Contents

Protein chains

(+ 0 more) 352 a.a.

Ligands

ATP ×6

References listed in PDB file

Key reference

• Title: Multiple conformations facilitate pilt function in the type IV pilus.
• Authors: M.Mccallum, S.Benlekbir, S.Nguyen, S.Tammam, J.L.Rubinstein, L.L.Burrows, P.L.Howell.
• Ref.: Nat Commun, 2019, 10, 5198. [DOI no: 10.1038/s41467-019-13070-z]
• PubMed id: 31729381

Abstract

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 C_2, 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.