Bidirectional pilus processing in the Tad pilus system motor CpaF.

Autor: Hohl M; Department of Infectious Disease, Imperial College, London, UK., Banks EJ; Department of Molecular Microbiology, John Innes Centre, Norwich, UK., Manley MP; Department of Infectious Disease, Imperial College, London, UK., Le TBK; Department of Molecular Microbiology, John Innes Centre, Norwich, UK., Low HH; Department of Infectious Disease, Imperial College, London, UK. h.low@imperial.ac.uk.
Jazyk: angličtina
Zdroj: Nature communications [Nat Commun] 2024 Aug 05; Vol. 15 (1), pp. 6635. Date of Electronic Publication: 2024 Aug 05.
DOI: 10.1038/s41467-024-50280-6
Abstrakt: The bacterial tight adherence pilus system (TadPS) assembles surface pili essential for adhesion and colonisation in many human pathogens. Pilus dynamics are powered by the ATPase CpaF (TadA), which drives extension and retraction cycles in Caulobacter crescentus through an unknown mechanism. Here we use cryogenic electron microscopy and cell-based light microscopy to characterise CpaF mechanism. We show that CpaF assembles into a hexamer with C2 symmetry in different nucleotide states. Nucleotide cycling occurs through an intra-subunit clamp-like mechanism that promotes sequential conformational changes between subunits. Moreover, a comparison of the active sites with different nucleotides bound suggests a mechanism for bidirectional motion. Conserved CpaF residues, predicted to interact with platform proteins CpaG (TadB) and CpaH (TadC), are mutated in vivo to establish their role in pilus processing. Our findings provide a model for how CpaF drives TadPS pilus dynamics and have broad implications for how other ancient type 4 filament family members power pilus assembly.
(© 2024. The Author(s).)
Databáze: MEDLINE
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