GENETICS OF FLAVIN DEHYDROGENASE-MEMBRANE INTERACTIONS

本研究的目的是确定黄素 沙门氏菌中的酶与膜相互作用 鼠伤寒。 这项工作将侧重于两个主要专题： 1. put操纵子的调控。 put操纵子有一个独特的 似乎是由putA基因介导的控制机制 产物，脯氨酸氧化酶。 当外源脯氨酸可用时， 脯氨酸氧化酶与细胞膜结合， 黄素脱氢酶;但在没有脯氨酸的情况下， 在细胞质中积累， 阻遏物 确定脯氨酸氧化酶如何控制其自身 表达可能有助于我们了解其他膜结合蛋白如何 调节蛋白起作用。 此外， putA突变提供了一个膜的遗传选择， 互作突变体 2. 黄素氧化酶-膜相互作用。 黄素 酶必须与膜结合， 与电子传递链适当地相互作用。 但 还不知道它们是如何与细胞膜相互作用的， 与之相互作用的电子传递链的组分 直接. 脯氨酸氧化酶互作的遗传研究 提供了一个模型系统， 蛋白质是如何在体内与细胞膜相互作用的。 蛋白质- 膜所需的蛋白质和蛋白质-脂质相互作用 关联可以通过分离突变体来确定， 防止脯氨酸氧化酶与膜结合。 遗传 对这些突变体的生化分析将表明 膜组分直接与黄素相互作用 以及需要哪些类型的交互 黄素氧化酶和膜电子 运输链。 这些突变体应该提供洞察力， 一个普遍的生物学问题， 与膜相互作用。

The objective of this study is to determine how flavin dehydrogenases interact with the membrane in Salmonella typhimurium. This work will focus on two main topics: 1. Regulation of the put operon. The put operon has a unique control mechanism that seems to be mediated by the putA gene product, proline oxidase. When exogenous proline is available, proline oxidase binds to the membrane where it functions as a flavin dehydrogenase; but in the absence of proline, it accumulates in the cytoplasm where it acts as an autogenous repressor. Determining how proline oxidase controls its own expression may help us understand how other membrane-bound regulatory proteins work. In addition, the regulatory properties of putA mutations provide a genetic selection for membrane interaction mutants. 2. Flavin dehydrogenase-membrane interactions. Flavin dehydrogenases must associate with the membrane in order to interact properly with the electron transport chain. However, it is not known how they interact with the membrane or what components of the electron transport chain they interact with directly. Genetic studies on the interaction of proline oxidase with the membrane provides a model system for understanding how proteins interact with membranes in vivo. The protein- protein and protein-lipid interactions required for membrane association can be determined by isolation of mutants that prevent proline oxidase from binding to the membrane. Genetic and biochemical analysis of these mutants will indicate what membrane component(s) directly interact with flavin dehydrogenases and what kinds of interactions are required between flavin dehydrogenases and the membrane electron transport chain. Such mutants should provide insight into the general biological problem of how peripheral membrane proteins interact with the membrane.