Structure of a proton-powered molecular motor that drives protein transport and gliding motility
Year: 2020
Type: preprint
Abstract: Summary Ion-driven motors are rare in biology. The archetypes of the three classes identified to date are ATP synthase, the bacterial flagellar motor, and a proton-driven motor that powers gliding motility and protein secretion in Bacteroidetes bacteria. Whilst the molecular mechanism of ATP synthase is now well understood, structural information is lacking for the other two classes of motor. Here we present the structure of the Bacteroidetes gliding motility motor determined by cryo-electron microscopy. The motor is an asymmetric inner membrane protein complex in which the single transmembrane helices of two periplasm-spanning GldM proteins are positioned within a ring of five GldL proteins. Combining mutagenesis and single-molecule tracking, we identify protonatable amino acid residues within the transmembrane domain of the complex that are important for motor function. Our data imply a mechanism in which proton flow leads the periplasm-spanning GldM dimer to rotate with respect to the intra-membrane GldL ring to drive processes at the bacterial outer membrane. This work provides a molecular basis for understanding how the gliding motility motor is able to transduce the energy of the inner membrane protonmotive force across the bacterial cell envelope.
Institutions: University of Oxford, Newcastle University
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
Awards: Molecular mechanisms in complement regulation and evasion., Moving folded proteins across membranes., Establishing a feeder EM facility for South Parks Road Oxford, Establishing a feeder EM facility for South Parks Road Oxford, Molecular mechanisms in complement regulation and evasion., Moving folded proteins across membranes., G6868616705
OpenAlex ID: W3025156016