Passmore Steven E, Meas Rithy, Marykwas Donna L
Department of Biological Sciences, California State University, Long Beach, Long Beach, CA 90840, USA.
Microbiology (Reading). 2008 Mar;154(Pt 3):714-724. doi: 10.1099/mic.0.2007/014597-0.
The Escherichia coli motor proteins FliM and FliG physically interact, presumably to control one or more of the functions of the bacterial flagellum clockwise/counterclockwise (CW/CCW) switch. We have previously demonstrated this interaction using the yeast two-hybrid system and have identified mutations in fliG that disrupt the interaction. Starting with the most interaction-defective of these fliG mutants, we mutagenized fliM to identify suppressor mutations that restore the FliM/FliG two-hybrid interaction. Certain fliM suppressor mutations exhibit allele specificity. These mutations help define a FliG-interaction surface on FliM. Moreover, the pattern of suppression suggests that two distinct sites on FliG interact with FliM, perhaps with two FliM molecules in a dimer per molecule of FliG.
大肠杆菌运动蛋白FliM和FliG存在物理相互作用，推测是为了控制细菌鞭毛顺时针/逆时针（CW/CCW）开关的一种或多种功能。我们之前使用酵母双杂交系统证明了这种相互作用，并鉴定出fliG中破坏这种相互作用的突变。从这些fliG突变体中相互作用缺陷最严重的开始，我们对fliM进行诱变以鉴定能恢复FliM/FliG双杂交相互作用的抑制突变。某些fliM抑制突变表现出等位基因特异性。这些突变有助于确定FliM上与FliG相互作用的表面。此外，抑制模式表明FliG上两个不同的位点与FliM相互作用，可能每个FliG分子与二聚体中的两个FliM分子相互作用。
