McEvoy M M, Dahlquist F W
Institute of Molecular Biology, University of Oregon, Eugene 97403-1229, USA.
Curr Opin Struct Biol. 1997 Dec;7(6):793-7. doi: 10.1016/s0959-440x(97)80148-0.
The movement of Gram-negative bacteria in response to nutrients in the environment is driven by two interlinked chemotaxis systems, the methyl-accepting chemotaxis protein (MCP)-mediated pathway, and the phosphoenolpyruvate: sugar phosphotransferase (PTS)-mediated pathway. The physical link connecting the two systems is unclear, but the common utilization of histidine-containing phosphocarrier proteins is an intriguing similarity. The recent structure determinations of several proteins from the PTS-mediated pathway, the phosphotransfer domain from the kinase CheA of the MCP-mediated chemotaxis pathway, and a homologous kinase, ArcB, enable the comparison of the histidine active sites of these systems. Overall, the tertiary folds of the proteins are quite different, as are the structural details of the histidine active sites within the proteins, and therefore there is not an obvious structural homolog via which the two pathways communicate, despite their similar chemical mechanisms.
革兰氏阴性菌对环境中营养物质作出反应的运动由两个相互关联的趋化系统驱动，即甲基接受趋化蛋白（MCP）介导的途径和磷酸烯醇丙酮酸：糖磷酸转移酶（PTS）介导的途径。连接这两个系统的物理联系尚不清楚，但含组氨酸的磷酸载体蛋白的共同利用是一个有趣的相似之处。最近对来自PTS介导途径的几种蛋白质、MCP介导的趋化途径的激酶CheA的磷酸转移结构域以及同源激酶ArcB的结构测定，使得能够比较这些系统的组氨酸活性位点。总体而言，这些蛋白质的三级结构相当不同，蛋白质内组氨酸活性位点的结构细节也是如此，因此，尽管这两个途径的化学机制相似，但并没有明显的结构同源物可作为它们之间通信的媒介。
