title: Conformational change in the periplamic region of the flagellar stator coupled with the assembly around the rotor.
abstract: The torque of the bacterial flagellum is generated by the rotor-stator interaction coupled with the ion flow through the channel in the stator. Anchoring the stator unit to the peptidoglycan layer with proper orientation around the rotor is believed to be essential for smooth rotation of the flagellar motor. The stator unit of the sodium-driven flagellar motor of Vibrio is composed of PomA and PomB, and is thought to be fixed to the peptidoglycan layer and the T-ring by the C-terminal periplasmic region of PomB. Here, we report the crystal structure of a C-terminal fragment of PomB (PomBC) at 2.0-Å resolution, and the structure suggests a conformational change in the N-terminal region of PomBC for anchoring the stator. On the basis of the structure, we designed double-Cys replaced mutants of PomB for in vivo disulfide cross-linking experiments and examined their motility. The motility can be controlled reproducibly by reducing reagent. The results of these experiments suggest that the N-terminal disordered region (121-153) and following the N-terminal two-thirds of α1(154-164) in PomBC changes its conformation to form a functional stator around the rotor. The cross-linking did not affect the localization of the stator nor the ion conductivity, suggesting that the conformational change occurs in the final step of the stator assembly around the rotor.
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan; and.
authors.forename: Shiwei
authors.initials: S
authors.lastname: Zhu
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
authors.forename: Masato
authors.initials: M
authors.lastname: Takao
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan; and.
authors.forename: Na
authors.initials: N
authors.lastname: Li
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan; and.
authors.forename: Mayuko
authors.initials: M
authors.lastname: Sakuma
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan; and.
authors.forename: Yuuki
authors.initials: Y
authors.lastname: Nishino
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan; and.
authors.forename: Michio
authors.initials: M
authors.lastname: Homma
authors.affiliation: Division of Biological Science, Graduate School of Science, Nagoya University, Chikusa-Ku, Nagoya 464-8602, Japan; and kimada@chem.sci.osaka-u.ac.jp z47616a@cc.nagoya-u.ac.jp.
authors.forename: Seiji
authors.initials: S
authors.lastname: Kojima
authors.affiliation: Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan kimada@chem.sci.osaka-u.ac.jp z47616a@cc.nagoya-u.ac.jp.
authors.forename: Katsumi
authors.initials: K
authors.lastname: Imada
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D003432:Cross-Linking Reagents / Q000378:metabolism; D003545:Cysteine / Q000235:genetics; D004220:Disulfides / Q000378:metabolism; D005407:Flagella / Q000187:drug effects / Q000378:metabolism*; D007477:Ions; D008958:Models, Molecular; D009154:Mutation / Q000235:genetics; D019897:Periplasm / Q000187:drug effects / Q000378:metabolism*; D017434:Protein Structure, Tertiary; D019163:Reducing Agents / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000378:metabolism; D014733:Vibrio / Q000187:drug effects / Q000378:metabolism
chemical_list: D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D004220:Disulfides; D007477:Ions; D019163:Reducing Agents; D013438:Sulfhydryl Compounds; D012964:Sodium; D003545:Cysteine
keywords: Vibrio alginolyticus; X-ray crystallography; ion-driven motor; peptidoglycan binding