The flagellar components of Vibrio spp., PomA and PomB, form a complex that transduces sodium ion and contributes to rotate flagella. The transmembrane protein PomB is attached to the basal body T-ring by its periplasmic region and has a plug segment following the transmembrane helix to prevent ion flux. Previously we showed that PomB deleted from E41 to R120 (Δ41–120) was functionally comparable to the full-length PomB. In this study, three deletions after the plug region, PomB (Δ61–120), PomB (Δ61–140), and PomB (Δ71–150), were generated. PomB (Δ61–120) conferred motility, whereas the other two mutants showed almost no motility in soft agar plate; however, we observed some swimming cells with speed comparable for the wild-type cells. When the two PomB mutants were introduced into a wild-type strain, the swimming ability was not affected by the mutant PomBs. Then, we purified the mutant PomAB complexes to confirm the stator formation. When plug mutations were introduced into the PomB mutants, the reduced motility by the deletion was rescued, suggesting that the stator was activated. Our results indicate that the deletions prevent the stator activation and the linker and plug regions, from E41 to S150, are not essential for the motor function of PomB but are important for its regulation.

中文翻译：

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PomB跨膜连接区和肽聚糖结合区在弧菌鞭毛运动能量转换中的作用

弧菌属的鞭毛成分PomA 和 PomB 形成复合物，可传导钠离子并有助于鞭毛旋转。跨膜蛋白 PomB 通过其周质区域附着在基体 T 形环上，并在跨膜螺旋后面有一个塞段以防止离子流动。之前我们表明，从 E41 到 R120 (Δ41-120) 删除的 PomB 在功能上与全长 PomB 相当。在本研究中，在插头区域后产生了三个缺失：PomB (Δ61–120)、PomB (Δ61–140) 和 PomB (Δ71–150)。 PomB (Δ61-120) 具有运动性，而其他两个突变体在软琼脂平板上几乎没有运动性；然而，我们观察到一些游泳细胞的速度与野生型细胞相当。当将两个PomB突变体引入野生型菌株时，游泳能力不受突变体PomB的影响。然后，我们纯化了突变体 PomAB 复合物以确认定子的形成。当将插头突变引入 PomB 突变体时，由于缺失而降低的运动性得以恢复，这表明定子被激活。我们的结果表明，删除阻止了定子激活，并且从 E41 到 S150 的连接子和插头区域对于 PomB 的运动功能并不重要，但对其调节很重要。