Solution structure analysis of the periplasmic region of bacterial flagellar motor stators by small angle X-ray scattering.

Autor: Liew CW; School of Medical Sciences, The University of New South Wales, Australia., Hynson RM; Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia., Ganuelas LA; School of Medical Sciences, The University of New South Wales, Australia., Shah-Mohammadi N; Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia; Climate Change Cluster, University of Technology Sydney, Ultimo, New South Wales, Australia., Duff AP; Australian Nuclear and Science Technology Organisation, Lucas Heights, New South Wales, Australia., Kojima S; Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan., Homma M; Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan., Lee LK; School of Medical Sciences, The University of New South Wales, Australia; Structural and Computational Biology Division, The Victor Chang Cardiac Research Institute, Darlinghurst, New South Wales, Australia. Electronic address: lawrence.lee@unsw.edu.au.
Jazyk: angličtina
Zdroj: Biochemical and biophysical research communications [Biochem Biophys Res Commun] 2018 Jan 08; Vol. 495 (2), pp. 1614-1619. Date of Electronic Publication: 2017 Dec 02.
DOI: 10.1016/j.bbrc.2017.11.194
Abstrakt: The bacterial flagellar motor drives the rotation of helical flagellar filaments to propel bacteria through viscous media. It consists of a dynamic population of mechanosensitive stators that are embedded in the inner membrane and activate in response to external load. This entails assembly around the rotor, anchoring to the peptidoglycan layer to counteract torque from the rotor and opening of a cation channel to facilitate an influx of cations, which is converted into mechanical rotation. Stator complexes are comprised of four copies of an integral membrane A subunit and two copies of a B subunit. Each B subunit includes a C-terminal OmpA-like peptidoglycan-binding (PGB) domain. This is thought to be linked to a single N-terminal transmembrane helix by a long unstructured peptide, which allows the PGB domain to bind to the peptidoglycan layer during stator anchoring. The high-resolution crystal structures of flagellar motor PGB domains from Salmonella enterica (MotB C2 ) and Vibrio alginolyticus (PomB C5 ) have previously been elucidated. Here, we use small-angle X-ray scattering (SAXS). We show that unlike MotB C2 , the dimeric conformation of the PomB C5 in solution differs to its crystal structure, and explore the functional relevance by characterising gain-of-function mutants as well as wild-type constructs of various lengths. These provide new insight into the conformational diversity of flagellar motor PGB domains and experimental verification of their overall topology.
(Copyright © 2017 Elsevier Inc. All rights reserved.)
Databáze: MEDLINE
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