Vibrio alginolyticus mutants resistant to phenamil, a specific inhibitor of the sodium-driven flagellar motor.
Vibrio alginolyticus mutants resistant to phenamil, a specific inhibitor of the sodium-driven flagellar motor.
复制标题
溶藻弧菌突变体对苯那米尔（一种钠驱动鞭毛运动的特异性抑制剂）具有抗性。
DOI：
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发表时间：
1997
影响因子：
5.6
通讯作者：
Michio Homma
中科院分区：
文献类型：
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作者：
S. Kojima;Tatsuo Atsumi;Kazumasa Muramoto;Seishi Kudo;I. Kawagishi;Michio Homma
溶藻弧菌的极性鞭毛由钠动力驱动，并且那些马达被非那米特异性地强烈抑制，非那米是一种阿米洛利类似物，被认为与鞭毛马达的钠通道相互作用。为了研究钠离子偶联位点，我们分离出了对非那米具有抗性的运动突变体，并将其命名为Mpa（r），表示对非那米具有抗性的运动。野生型（Mpa（s））的运动性被50 μ M非那敏抑制，而Mpa（r）菌株在200 μ M非那敏存在下仍然运动。在Mpa（r）菌株中，非那灭的Ki值估计比Mpa（s）菌株中的Ki值大5倍。然而，在Mpa（r）菌株中，对阿米洛利或另一种阿米洛利类似物苯扎米尔的敏感性没有明显改变。野生型Na+驱动电机的旋转速率在非那灭的存在下波动很大，这可以解释为非那灭从电机的解离速率相对较慢。因此，我们研究了由phenamil的Mpa（r）和Mpa（s）电机的旋转稳定性。Mpa（r）电机的速度波动相对于Mpas电机明显减小。Mpa（r）马达的更快旋转可以通过马达的钠通道的非那灭解离速率的增加来解释，这表明马达的非那灭特异性结合位点在Mpa（r）菌株中发生突变。
The polar flagella of Vibrio alginolyticus are driven by sodium motive force and those motors are specifically and strongly inhibited by phenamil, an amiloride analog that is thought to interact with a sodium channel of the flagellar motor. To study the sodium ion coupling site, we isolated motility mutants resistant to phenamil and named the phenotype Mpa(r) for motility resistant to phenamil. The motility of the wild-type (Mpa(s)) was inhibited by 50 microM phenamil, whereas Mpa(r) strains were still motile in the presence of 200 microM phenamil. The Ki value for phenamil in the Mpa(r) strain was estimated to be five times larger than that in the Mpa(s) strain. However, the sensitivities to amiloride or benzamil, another amiloride analog, were not distinctly changed in the Mpa(r) strain. The rotation rate of the wild-type Na+-driven motor fluctuates greatly in the presence of phenamil, which can be explained in terms of a relatively slow dissociation rate of phenamil from the motor. We therefore studied the stability of the rotation of the Mpa(r) and Mpa(s) motors by phenamil. The speed fluctuations of the Mpa(r) motors were distinctly reduced relative to the Mpas motors. The steadier rotation of the Mpa(r) motors can be explained by an increase in the phenamil dissociation rate from a sodium channel of the motor, which suggests that a phenamil-specific binding site of the motor is mutated in the Mpa(r) strain.