Zentrum für Molekulare Biologie der Universität Heidelberg, DKFZ-ZMBH Alliance, Im Neuenheimer Feld 282, D-69120 Heidelberg, Germany.
Mol Microbiol. 2011 May;80(4):886-99. doi: 10.1111/j.1365-2958.2011.07557.x. Epub 2011 Feb 10.
Bacterial flagellar motor is a highly ordered and complex supramolecular structure that powers rotation of flagella and serves as a type III export apparatus for flagellar assembly. Motor biogenesis represents a formidable example of self-assembly, but little is known about early steps of the motor structure formation. Here we used a combination of fluorescence microscopy techniques to dissect the order of the motor assembly in Escherichia coli cells, to map in vivo the underlying protein interactions and to investigate dynamics of protein exchange in the assembled motor structure. Our data suggest that motor self-assembly is initiated by oligomerization of the membrane export apparatus protein FlhA, which is followed by the recruitment of the MS ring component FliF and by the ordered association of other motor proteins. The assembly process combines the hierarchy with cooperativity, whereby the association of each subsequent motor structure stabilizes the growing assembly. Our results provide a novel and so far the most complete view of the early steps in flagellar motor assembly and improve understanding of the motor structure and regulation.
细菌鞭毛马达是一种高度有序和复杂的超分子结构，它为鞭毛的旋转提供动力，并作为鞭毛组装的 III 型输出装置。马达的生物发生代表了自组装的一个令人敬畏的例子，但对于马达结构形成的早期步骤知之甚少。在这里，我们使用荧光显微镜技术的组合来剖析大肠杆菌细胞中马达组装的顺序，绘制体内潜在的蛋白质相互作用，并研究组装的马达结构中蛋白质交换的动力学。我们的数据表明，马达的自组装是由膜输出装置蛋白 FlhA 的寡聚化启动的，随后是 MS 环成分 FliF 的募集，以及其他马达蛋白的有序结合。组装过程将层次结构与协同作用结合在一起，从而使每个后续马达结构的结合稳定了正在生长的组装体。我们的结果提供了鞭毛马达组装早期步骤的一个新颖的、迄今为止最完整的视图，并提高了对马达结构和调节的理解。
