Solution structure analysis of the periplasmic region of bacterial flagellar motor stators by small angle X-ray scattering
Autor: | Robert M.G. Hynson, Michio Homma, Lawrence K. Lee, Anthony P. Duff, Seiji Kojima, N Shah-Mohammadi, Chu Wai Liew, Lorraine A Ganuelas |
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Rok vydání: | 2017 |
Předmět: |
0301 basic medicine
Models Molecular Protein subunit 030106 microbiology Biophysics Biochemistry law.invention 03 medical and health sciences chemistry.chemical_compound Bacterial Proteins Protein Domains X-Ray Diffraction law Scattering Small Angle Inner membrane Amino Acid Sequence Protein Structure Quaternary Molecular Biology Vibrio alginolyticus Sequence Homology Amino Acid Rotor (electric) Chemistry Molecular Motor Proteins Salmonella enterica Cell Biology Periplasmic space Recombinant Proteins Solutions Transmembrane domain 030104 developmental biology Structural biology Flagella Mechanosensitive channels Peptidoglycan Bacterial Outer Membrane Proteins |
Zdroj: | Biochemical and biophysical research communications. 495(2) |
ISSN: | 1090-2104 |
Popis: | 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 (MotBC2) and Vibrio alginolyticus (PomBC5) have previously been elucidated. Here, we use small-angle X-ray scattering (SAXS). We show that unlike MotBC2, the dimeric conformation of the PomBC5 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. |
Databáze: | OpenAIRE |
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