Properties of motility in Bacillus subtilis powered by the H+-coupled MotAB flagellar stator, Na+-coupled MotPS or hybrid stators MotAS or MotPB
Properties of motility in Bacillus subtilis powered by the H+-coupled MotAB flagellar stator, Na+-coupled MotPS or hybrid stators MotAS or MotPB
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DOI：
10.1016/j.jmb.2005.07.030
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发表时间：
2005-09-16
影响因子：
5.6
通讯作者：
Krulwich, TA
中科院分区：
文献类型：
--
作者：
Ito, M;Terahara, N;Krulwich, TA
枯草芽孢杆菌有一个单一的鞭毛转子蛋白，相互作用的两个不同的定子力发生器，H+耦合MotAB复合物和Na+耦合MotPS复合物，能源旋转。在此，在野生型B中测定软琼脂平板和液体中的运动性。枯草杆菌和仅表达一个定子（MotAB、MotPS或杂交MotAS或MotPB）的菌株。表达MotAB或MotAS的菌株具有平均11个鞭毛/细胞，而表达MotPS或MotPB的菌株具有平均7个鞭毛/细胞，并且无Mot-less双突变体具有3至4个鞭毛/细胞。在大多数条件下，MotAB比MotPS在运动中具有更主导的作用，但MotPS在含苹果酸盐的软琼脂平板培养基上在升高的pH和Na+下支持与MotAB相当的运动性。MotAB支持更快的游泳速度在液体中比MotPS，MotAS或MotPB在所有条件下，但MotPS对野生型游泳的贡献是可辨别的游泳速度在升高的粘度，pH值和Na+的野生型和MotAB的差异。由MotPS和MotAS支持的游泳被Na+和升高的pH刺激，而MotAB和MotPB则匡威。这表明MotAS是Na+-偶联的，MotPB是H+-偶联的，MotB和MotS是离子偶联的主要决定因素。然而，在Na+浓度高于300 mM时，MotPB以及MotPS和MotAS支持的游泳速度受到严重抑制，而MotAB依赖性游泳则没有。定子中MotP或MotS组分的存在也赋予了对阿米洛利类似物抑制的敏感性。这些观察结果表明，MotP有助于Na+耦合和抑制Na+通道抑制剂。类似地，MotA在H+依赖的定子性能中的作用由pH对MotAS与MotPS的Na+响应的较大影响指示。最后，仅在MotPS和MotPB中发现在升高的粘度下的最佳功能，因此由MotP赋予。(c)2005爱思唯尔有限公司保留所有权利。
Bacillus subtilis has a single set of flagellar rotor proteins that interact with two distinct stator-force generators, the H+-coupled MotAB complex and the Na+-coupled MotPS complex, that energize rotation. Here, motility on soft agar plates and in liquid was assayed in wild-type B. subtilis and strains expressing only one stator, either MotAB, MotPS or hybrid MotAS or MotPB. The strains expressing MotAB or MotAS had an average of 11 flagella/cell while those expressing MotPS or MotPB had an average of seven flagella/cell, and a Mot-less double mutant had three to four flagella/cell. MotAB had a more dominant role in motility than MotPS under most conditions, but MotPS supported comparable motility to MotAB on malate-containing soft agar plating media at elevated pH and Na+. MotAB supported much faster swimming speeds in liquid than MotPS, MotAS or MotPB under all conditions, but a contribution of MotPS to wild-type swimming was discernible from differences in swimming speeds of wild-type and MotAB at elevated viscosity, pH and Na+. Swimming supported by MotPS and MotAS was stimulated by Na+ and elevated pH whereas the converse was true of MotAB and MotPB. This suggests that MotAS is Na+-coupled and MotPB is H+-coupled and that MotB and MotS are major determinants of ion-coupling. However, the swimming speed supported by MotPB, as well as MotPS and MotAS, was inhibited severely at Na+ concentrations above 300 mM whereas MotAB-dependent swimming was not. The presence of either the MotP or MotS component in the stator also conferred sensitivity to inhibition by an amiloride analogue. These observations suggest that MotP contributes to Na+-coupling and inhibition by Na+ channel inhibitors. Similarly, a role for MotA in H+-dependent stator properties is indicated by the larger effects of pH on the Na+-response of MotAS versus MotPS. Finally, optimal function at elevated viscosity was found only in MotPS and MotPB and is therefore conferred by MotP. (c) 2005 Elsevier Ltd. All rights reserved.