Roles of the Escherichia coli proteins FliG, FliM, and FliN in flagellar rotation

许多细菌是由可逆的旋转马达推动的，这些马达从质子运动梯度中获得旋转的能量。在构建一个功能齐全的马达所需的许多蛋白质中，有五个最有可能参与扭矩产生的蛋白质，分别是MoTA、MOTB、FliG、Flim和Flin。FliG、FliM和Flin对组装和决定旋转方向也很重要；这些被称为“开关复合体”蛋白质。我们将研究开关复合体蛋白在扭矩产生中的作用，利用分子遗传学使这些成分发生突变，并对运动性能进行详细测量，以评估后果。这些蛋白质的受控、低水平表达的效果也将得到检验。这一策略类似于以前研究MOTA和MOTB时使用的策略。这些研究的长期目标是在分子水平上了解鞭毛马达如何将化学能转化为机械能。了解能量转换的机制是生物能量学的核心问题。此外，由于运动性在某些细菌感染中发挥作用，了解鞭毛运动可能具有临床意义。

Many bacteria are propelled by reversible rotary motors which derive the energy for rotation from a protonmotive gradient. Among the many proteins required to build a fully functional motor, there are five, called MotA, MotB, FliG, FliM, and FliN, that are most likely to be involved in torque generation. FliG, FliM, and FliN are also important for assembly and for determining the direction of rotation; these are called "switch-complex" proteins. The roles of the switch-complex proteins in torque generation will be examined, using molecular genetics to make mutations in these components, and detailed measurements of motor performance to assess the consequences. The effects of controlled, low-level expression of theses proteins also will be examined. This strategy is similar to that used previously to study MotA and MotB. The long-term objective of these studies is to understand, at the molecular level, how the flagellar motor converts chemical energy into mechanical energy. Understanding mechanisms of energy conversion is a central concern in bioenergetics. Also since motility plays a role in certain bacterial infections, understanding the flagellar motor is likely to have clinical significance.