Multiple conformations facilitate PilT function in the type IV pilus.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 31729381.
- Also identified by DOI 10.1038/s41467-019-13070-z and PMC identifier 6858323.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
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 C<sub>2</sub> symmetry; however, most of these ATPases crystallize with either C<sub>3</sub> or C<sub>6</sub> 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<sub>2,</sub> C<sub>3</sub>, and C<sub>6</sub> 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 C<sub>2</sub> conformation. With these data, we propose a comprehensive model of PilT function with broad implications for PilT/VirB11-like family members.
Medical subject headings
- Adenosine Triphosphatases
- Bacterial Proteins
- Caulobacter
- Fimbriae, Bacterial