Structural insight into sodium ion pathway in the bacterial flagellar stator from marine Vibrio

• 成果类型: Article
• 署名作者: Nishikino, Tatsuro; Takekawa, Norihiro; Kishikawa, Jun-ichi; Hirose, Mika; Kojima, Seiji; Homma, Michio; Kato, Takayuki; Imada, Katsumi
• 署名单位: University of Osaka; Nagoya Institute of Technology; Nagoya Institute of Technology; University of Osaka; Kyoto Institute of Technology; Nagoya University
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12501
• DOI: 10.1073/pnas.2415713122
• 发表日期: 2025-01-07
• 关键词: charged residues; rhodobacter-sphaeroides; periplasmic region; torque generation; escherichia-coli; driven; motor; protein; rotor; pomb

摘要

Many bacteria swim in liquid or swarm on surface using the flagellum rotated by a motor driven by specific ion flow. The motor consists of the rotor and stator, and the stator converts the energy of ion flow to mechanical rotation. However, the ion pathway and the mechanism of stator rotation coupled with specific ion flow are still obscure. Here, we determined the structures of the sodium- driven stator of Vibrio, namely PomAB, in the presence and absence of sodium ions and the structure with its specific inhibitor, phenamil, by cryo- electron microscopy. The structures and following functional analysis revealed the sodium ion pathway, the mechanism of ion selectivity, and the inhibition mechanism by phenamil. We propose a model of sodium ion flow coupled with the stator rotation based on the structures. This work provides insights into the molecular mechanisms of ion specificity and conversion of the electrochemical potential into mechanical functions.