ISOLATION, CHARACTERIZATION AND STRUCTURE OF BACTERIAL FLAGELLAR MOTORS CONTAINING THE SWITCH COMPLEX
ISOLATION, CHARACTERIZATION AND STRUCTURE OF BACTERIAL FLAGELLAR MOTORS CONTAINING THE SWITCH COMPLEX
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DOI：
10.1006/jmbi.1994.1079
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发表时间：
1994-01-28
影响因子：
5.6
通讯作者：
DEROSIER, DJ
中科院分区：
文献类型：
--
作者：
FRANCIS, NR;SOSINSKY, GE;DEROSIER, DJ
一个假定的复合物的三个开关蛋白，FliG，FliM和FliN似乎直接参与扭矩的产生和控制的旋转方向。我们已经开发了一种鞭毛马达的制备方法，该方法保留了这些蛋白质，如使用抗FliG、抗FliM和抗FliN抗体的蛋白质印迹所证明的。用这三种抗体进行免疫金标记显示，这三种开关蛋白定位于马达。冷冻水化制剂的电子显微镜照片显示了一个大的，新的组件，我们称之为“C环复合物”连接到细胞质的M环。在三维重建的圆柱形平均结构，M-S环复合物似乎更厚，更宽的额外的材料添加到细胞质表面的M环。此外，从增厚的M环延伸到细胞质中的是C环复合物，与M环的290 μ m直径相比，C环复合物是一个薄壁圆柱体，长度为170 μ m，外径为450 μ m。我们提供的证据表明，增厚的M环含有FliG和C环复合物可能含有FliM和FliN。C环复合物的大直径可能允许与M环和被认为是MotA/MotB复合物的螺柱环相互作用。
A putative complex of the three switch proteins, FliG, FliM and FliN appears to be directly involved in torque generation and control of direction of rotation. We have developed a preparative procedure for flagellar motors that retains these proteins as evidenced by Western blots using anti-FliG, anti-FliM and anti-FliN antibodies. Immunogold labeling with these three antibodies shows that the three switch proteins are localized to the motor. Electron micrographs of frozen-hydrated preparations reveal a large, new component we have termed the "C ring complex" attached to the cytoplasmic face of the M ring. In a three-dimensional reconstruction of the cylindrically averaged structure, the M-S ring complex appears thicker and wider by the addition of extra material to the cytoplasmic surface of the M ring. In addition, extending into the cytoplasm from the thickened M ring is the C ring complex, a thin-walled cylinder having a length of 170 Å and an outer diameter of 450 Å compared to the 290 Å diameter of the M ring. We provide evidence that the thickened M ring contains FliG and that the C ring complex may contain FliM and FliN. The large diameter of the C ring complex may permit interaction with the M ring and with the circlet of studs thought to be the MotA/MotB complex.