文章基本信息

标题：A novel type bacterial flagellar motor that can use divalent cations as a coupling ion
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作者：Riku Imazawa ; Yuka Takahashi ; Wataru Aoki 等
期刊名称：Scientific Reports
电子版ISSN：2045-2322
出版年度：2016
卷号：6
期号：1
DOI：10.1038/srep19773
语种：English
出版社：Springer Nature
摘要：The bacterial flagellar motor is a sophisticated nanomachine embedded in the cell envelope and powered by an electrochemical gradient of H⁺, Na⁺, or K⁺across the cytoplasmic membrane. Here we describe a new member of the bacterial flagellar stator channel family (MotAB1 of Paenibacillus sp. TCA20 (TCA-MotAB1)) that is coupled to divalent cations (Ca²⁺and Mg²⁺). In the absence of divalent cations of alkaline earth metals, no swimming was observed in Paenibacillus sp. TCA20, which grows optimally in Ca²⁺-rich environments. This pattern was confirmed by swimming assays of a stator-free Bacillus subtilis mutant expressing TCA-MotAB1. Both a stator-free and major Mg²⁺uptake system-deleted B. subtilis mutant expressing TCA-MotAB1 complemented both growth and motility deficiency under low Mg²⁺conditions and exhibited [Mg²⁺]_in identical to that of the wild-type. This is the first report of a flagellar motor that can use Ca²⁺and Mg²⁺as coupling ions. These findings will promote the understanding of the operating principles of flagellar motors and molecular mechanisms of ion selectivity.