Oosawa K, Ueno T, Aizawa S
Department of Biosciences, School of Science and Engineering, Teikyo University, Utsunomiya, Japan.
J Bacteriol. 1994 Jun;176(12):3683-91. doi: 10.1128/jb.176.12.3683-3691.1994.
The flagellar switch proteins (FliG, FliM, and FliN) of Salmonella typhimurium were overproduced in Escherichia coli and partially purified in soluble form. They were mixed with purified MS ring complexes (which consist of subunits of FliF protein) to examine their interactions in vitro. The degree of interaction was estimated by ultracentrifugation, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. From the band density on the gel, we estimated that FliG bound to the MS ring complex at an approximately 1:1 molar ratio (FliG:FliF), whereas FliM did so only at a 1:5 molar ratio (FliM:FliF). FliN did not bind to the MS ring complex by itself or in the presence of the other switch proteins. A possible configuration of the switch proteins is discussed.
鼠伤寒沙门氏菌的鞭毛开关蛋白（FliG、FliM和FliN）在大肠杆菌中过量表达，并以可溶形式部分纯化。将它们与纯化的MS环复合物（由FliF蛋白亚基组成）混合，以检测它们在体外的相互作用。通过超速离心，随后进行十二烷基硫酸钠-聚丙烯酰胺凝胶电泳来估计相互作用的程度。根据凝胶上的条带密度，我们估计FliG以大约1:1的摩尔比（FliG:FliF）与MS环复合物结合，而FliM仅以1:5的摩尔比（FliM:FliF）结合。FliN自身或在其他开关蛋白存在的情况下均不与MS环复合物结合。文中讨论了开关蛋白的一种可能构型。
