Mutations conferring resistance to phenamil and amiloride, inhibitors of sodium-driven motility of Vibrio parahaemolyticus
Mutations conferring resistance to phenamil and amiloride, inhibitors of sodium-driven motility of Vibrio parahaemolyticus
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DOI：
10.1073/pnas.96.10.5740
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发表时间：
1999-05-11
影响因子：
11.1
通讯作者：
McCarter, LL
中科院分区：
文献类型：
--
作者：
Jaques, S;Kim, YK;McCarter, LL
细菌的鞭毛由一个旋转马达驱动，它能够以非常高的速度转动螺旋状的鞭毛推进器。驱动旋转的能量来自特定离子的跨膜电化学电势。通过通道组件的离子被认为是产生旋转动力的力。本文介绍了两种基于不同耦合离子的马达：质子驱动马达和钠驱动马达。有四个已知的基因编码组件的钠供电的极性鞭毛马达在副溶血弧菌，Typo，其特征在于在这里，是同源的基因编码的质子型马达（motA和motB）的成分，和两个编码组件独特的钠型马达（motX和motY）。钠通道阻断药物非那灭和阿米洛利抑制极鞭毛的旋转，因此可以用来探测马达的结构。分离出在非那米或阿米洛利存在下可以游泳的突变体。大多数赋予非那米抗性运动性的突变改变了motA或motB基因中的核苷酸。由此产生的氨基酸变化定位于扭矩发生器的细胞质面，并允许识别潜在的钠相互作用位点。在阿米洛利存在下赋予运动性的突变不改变钠型鞭毛马达的任何已知组分。因此，有证据支持存在不止一类钠相互作用位点，在这些位点上抑制剂可以干扰钠驱动的运动。
The bacterial flagellum is powered by a rotary motor capable of turning the helical flagellar propeller at very high speeds. Energy to drive rotation is derived from the transmembrane electrochemical potential of specific ions. Ions passing through a channel component are thought to generate the force to power rotation. Two kinds of motors, dependent on different coupling ions, have been described: proton-driven and sodium-driven motors. There are four known genes encoding components of the sodium-powered polar flagellar motor in Vibrio parahaemolyticus, Typo, which are characterized here, are homologous to genes encoding constituents of the proton-type motor (motA and motB), and two encode components unique to the sodium-type motor (motX and motY). The sodium-channel-blocking drugs phenamil and amiloride inhibit rotation of the polar flagellum and therefore can be used to probe the architecture of the motor. Mutants were isolated that could swim in the presence of phenamil or amiloride, The majority of the mutations conferring phenamil-resistant motility alter nucleotides in the motA or motB genes. The resultant amino acid changes localize to the cytoplasmic face of the torque generator and permit identification of potential sodium-interaction sites. Mutations that confer motility in the presence of amiloride do not alter any known component of the sodium-type flagellar motor. Thus, evidence supports the existence of more than one class of sodium-interaction site at which inhibitors can interfere with sodium-driven motility.