Roles of Charged Residues of Rotor and Stator in Flagellar Rotation: Comparative Study using H+-Driven and Na+-Driven Motors in Escherichia coli
Roles of Charged Residues of Rotor and Stator in Flagellar Rotation: Comparative Study using H+-Driven and Na+-Driven Motors in Escherichia coli
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DOI：
10.1128/jb.188.4.1466-1472.2006
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发表时间：
2006-02
影响因子：
3.2
通讯作者：
T. Yakushi;Junghoon Yang;Hajime Fukuoka;M. Homma;D. Blair
中科院分区：
文献类型：
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作者：
T. Yakushi;Junghoon Yang;Hajime Fukuoka;M. Homma;D. Blair
摘要在大肠杆菌中，鞭毛马达的旋转依赖于定子蛋白MoTA和转子蛋白FliG之间的带电残基之间的静电相互作用。这些带电残基在Na+驱动的溶藻弧菌的极鞭毛中保守，但在溶藻弧菌中的突变研究表明，它们对运动旋转相对不重要。因此，在大肠杆菌中检测到的静电相互作用可能不是鞭毛马达的一般特征，或者，溶藻弧菌马达可能依赖于类似的相互作用，但包含了额外的特征，使其对突变更健壮。在这里，我们对驻留在大肠杆菌中的嵌合电机进行了比较研究，但设计使用了溶藻弧菌的定子组件、转子组件或两者都使用。溶藻弧菌转子和定子蛋白中的带电残基被发现对发动机旋转是必不可少的，当这些蛋白质在大肠杆菌发动机的设置中发挥作用时。转子/定子双突变体中的协同和抑制模式表明，溶藻弧菌蛋白的相互作用方式基本上与它们在大肠杆菌中的同类蛋白相同。溶藻弧菌转子-定子界面的稳定性部分是由于POMA中存在额外的带电残基，但主要是由于其他因素，因为同时使用溶藻弧菌转子和定子成分的大肠杆菌发动机对突变仍然敏感。溶藻弧菌的运动功能可能被MotX和Moty蛋白增强。
ABSTRACT In Escherichia coli, rotation of the flagellar motor has been shown to depend upon electrostatic interactions between charged residues of the stator protein MotA and the rotor protein FliG. These charged residues are conserved in the Na+-driven polar flagellum of Vibrio alginolyticus, but mutational studies in V. alginolyticus suggested that they are relatively unimportant for motor rotation. The electrostatic interactions detected in E. coli therefore might not be a general feature of flagellar motors, or, alternatively, the V. alginolyticus motor might rely on similar interactions but incorporate additional features that make it more robust against mutation. Here, we have carried out a comparative study of chimeric motors that were resident in E. coli but engineered to use V. alginolyticus stator components, rotor components, or both. Charged residues in the V. alginolyticus rotor and stator proteins were found to be essential for motor rotation when the proteins functioned in the setting of the E. coli motor. Patterns of synergism and suppression in rotor/stator double mutants indicate that the V. alginolyticus proteins interact in essentially the same way as their counterparts in E. coli. The robustness of the rotor-stator interface in V. alginolyticus is in part due to the presence of additional charged residues in PomA but appears mainly due to other factors, because an E. coli motor using both rotor and stator components from V. alginolyticus remained sensitive to mutation. Motor function in V. alginolyticus may be enhanced by the proteins MotX and MotY.