Sodium-dependent dynamic assembly of membrane complexes in sodium-driven flagellar motors
Sodium-dependent dynamic assembly of membrane complexes in sodium-driven flagellar motors
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DOI：
10.1111/j.1365-2958.2008.06569.x
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发表时间：
2009-02-01
影响因子：
3.6
通讯作者：
Homma, Michio
中科院分区：
文献类型：
--
作者：
Fukuoka, Hajime;Wada, Tomoyuki;Homma, Michio
细菌鞭毛马达是由特定离子H+或Na+的电化学势驱动的。电机由转子和定子组成，它们的相互作用产生旋转。在溶藻弧菌的Na+马达中，定子由Poma和Pomb组成，被认为是一个扭矩发生器，将离子通量的能量转化为机械能。我们发现，包括D24N、F33C和S248F在内的Pomb基因上的特定突变导致了运动性缺陷，影响了利用绿色荧光蛋白融合的定子蛋白将定子复合体组装到极地鞭毛马达中。Pomb的D24是预测的Na+结合部位。此外，我们还证明了耦合离子Na+是定子组装所必需的，而非那米(Na+驱动电机的抑制剂)抑制了这种组装。羰基氰化物间氯苯肼，这是一个质子离子载体，在中性pH下使生物体内的钠动力崩溃，也抑制了组装。因此，我们得出结论，Na+通过通道的内流过程，包括Na+结合，对于定子复合体组装到鞭毛马达以及扭矩的产生是必不可少的。
The bacterial flagellar motor is driven by the electrochemical potential of specific ions, H+ or Na+. The motor consists of a rotor and stator, and their interaction generates rotation. The stator, which is composed of PomA and PomB in the Na+ motor of Vibrio alginolyticus, is thought to be a torque generator converting the energy of ion flux into mechanical power. We found that specific mutations in PomB, including D24N, F33C and S248F, which caused motility defects, affected the assembly of stator complexes into the polar flagellar motor using green fluorescent protein-fused stator proteins. D24 of PomB is the predicted Na+-binding site. Furthermore, we demonstrated that the coupling ion, Na+, is required for stator assembly and that phenamil (an inhibitor of the Na+-driven motor) inhibited the assembly. Carbonyl cyanide m-chlorophenylhydrazone, which is a proton ionophore that collapses the sodium motive force in this organism at neutral pH, also inhibited the assembly. Thus we conclude that the process of Na+ influx through the channel, including Na+ binding, is essential for the assembly of the stator complex to the flagellar motor as well as for torque generation.