STUDIES OF TRIMETHYLAMINE DEHYDROGENASE

描述：(改编自申请人的摘要)该计划的总体目标 建议进行的研究是为了更深入地了解丹参的作用机制 三甲胺脱氢酶(TMADH)是一类重要的酶 它包含多个氧化还原活性中心，并具有整体催化作用 涉及这些位置之间的电子转移的机制。除了……之外 它们的生理意义，这些蛋白质是非常有用的 一种系统，用来检查控制磁力和磁力的因素 这些中心之间的电子转移相互作用。该反应由以下物质催化 三甲胺氧化脱甲基化为二甲胺和 甲醛，对理解 生物体系中可用于异四氧嘧啶环的化学。这 化学与许多其他酶有关，包括临床上的 重要的酶，如单胺氧化酶。 拟议的工作建立在国际和平研究所以前的工作基础上，并具有以下内容 主要目标：研究特定氨基酸残基的作用 在TMADH催化的反应中；TMADH反应的表征 使用时间分辨结晶学；描述异常强烈的 TMADH的黄素中心和Fe4S4中心之间的磁性相互作用； 电化学性质和电子转移性质的检测 TMADH；以及三甲胺相互作用的表征 脱氢酶及其生理电子受体，以及 电子转移黄素蛋白。以立体结构为导向 在三甲胺脱氢酶中，特定氨基酸残基在 与这些区域相关的酶的活性部位为 通过定点突变来解决。这项工作的目的是 构建结构与功能关系的全面图景 在三甲胺脱氢酶中，进一步加深了我们对 这种酶和相关酶的作用机制。

DESCRIPTION: (adapted from applicant's abstract) The overall goal of the proposed research is to gain deeper insight into the mechanism of action of trimethylamine dehydrogenase (TMADH), a member of an important group of enzymes that contain multiple redox-active centers and which have overall catalytic mechanisms involving electron transfer between these sites. In addition to their physiological significance, these proteins serve as extremely useful systems in which to examine the factors which govern the magnetic and electron-transfer interactions between such centers. The reaction catalyzed by TMADH, the oxidative demethylation of trimethylamine to dimethylamine and formaldehyde, is of considerable intrinsic interest in understanding the chemistry available to the isoalloxazine ring in biological systems. This chemistry is relevant to a number of other enzymes, including such clinically important enzymes as monoamine oxidase. The proposed work builds on previous work by the PI and has the following principal objectives: Examination of the role of specific amino acid residues in the reaction catalyzed by TMADH; characterization of the reaction of TMADH using time-resolved crystallography; characterization of the unusually strong magnetic interaction between the flavin and Fe4S4 semiquinone centers of TMADH; examination of the electrochemical and electron-transferring properties of TMADH; and characterization of the interaction between trimethylamine dehydrogenase and its physiological electron acceptor, and electron-transferring flavoprotein. Guided by the three-dimensional structure of trimethylamine dehydrogenase, the roles of specific amino acid residues in the active site of the enzyme with regard to each of these areas will be addressed by site-directed mutagenesis. The intention of this work is to construct a comprehensive picture of the relationship of structure to function in trimethylamine dehydrogenase that furthers our basic understanding of the mechanism of this and related enzymes.