SUCCESSIVE INCORPORATION OF FORCE-GENERATING UNITS IN THE BACTERIAL ROTARY MOTOR
SUCCESSIVE INCORPORATION OF FORCE-GENERATING UNITS IN THE BACTERIAL ROTARY MOTOR
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DOI：
10.1038/309470a0
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发表时间：
1984-01-01
期刊：
影响因子：
64.8
通讯作者：
BERG, HC
中科院分区：
文献类型：
--
作者：
BLOCK, SM;BERG, HC
大肠杆菌的运动突变体是瘫痪的：它们的鞭毛似乎是完整的，但不旋转1。MotA和MotB基因产物存在于细胞质膜2中;它们不与在中性洗涤剂中分离的鞭毛基体共纯化1。Silverman等人发现，突变体可以通过携带野生型基因的λ转导载体指导蛋白质合成而“复活”。在这里，我们研究了这种激活的水平上的一个单一的鞭毛电机。携带质粒的amotB菌株的细胞通过单个鞭毛被拴在玻璃表面上，在所述质粒中野生型amotB基因的转录由lac启动子控制。这些细胞在加入alacinducer后几分钟内开始旋转，它们的旋转速度以一系列等间隔的步骤变化。在单个细胞中可以看到多达7个步骤，从最终获得的速度可以推断出多达16个步骤。这些实验表明，每个鞭毛马达包含几个独立的力产生单位组成，至少部分，motB蛋白。
Motmutants ofEscherichia coliare paralysed: their flagella appear to be intact but do not rotate1. ThemotAandmotBgene products are found in the cytoplasmic membrane2; they do not co-purify with flagellar basal bodies isolated in neutral detergents1. Silvermanet al.found thatmotmutants could be ‘resurrected’ through protein synthesis directed by λ transducing phages carrying the wild-type genes2. Here, we have studied this activation at the level of a single flagellar motor. Cells of amotBstrain carrying plasmids in which transcription of the wild-typemotBgene was controlled by thelacpromoter were tethered to a glass surface by a single flagellum. These cells began to spin within several minutes after the addition of alacinducer, and their rotational speed changed in a series of equally spaced steps. As many as 7 steps were seen in individual cells and, from the final speeds attained, as many as 16 steps could be inferred. These experiments show that each flagellar motor contains several independent force-generating units comprised, at least in part, of motB protein.