STRUCTURE/FUNCTION & BIOSYNTHESIS OF RESPIRATORY ENZYMES

描述：该项目的目标是定义 部分藜麦蛋白脱氢酶的催化和电子转移(ET) 以及它们的生理蛋白质氧化还原伙伴。这些蛋白质正被用于 开发和检验关于(I)蛋白质结合的作用的假说 催化和内质网中的醌辅助因子，(II)长程作用机理 蛋白质间ET反应，以及(Iii)稳定特异性的因子。 促进分子间ET的可溶性蛋白质之间的相互作用。 生理性ET反应的研究在很大程度上局限于 结构信息难以确定的整体膜蛋白 获取。藜麦蛋白脱氢酶是可溶的，有两个相对的 独特而有趣的特性。它们利用酶结合的苯醌作为 假体基团，对于电子受体，他们使用其他蛋白质 而不是O2或吡啶核苷酸。我们正在描述催化反应 藜麦蛋白的作用机制及其ET动力学模型的建立 反应，并确定这些蛋白质的晶体结构 具有生理氧化还原伙伴的复合体。这使得我们能够关联 结构信息与我们的研究结果。这样做的一个主要目的是 建议使用定点突变来检验假设，这些假设 关于催化、蛋白质-蛋白质机制的研究进展 交互作用和远程ET。对影响因素的解释 藜麦蛋白及其受体之间的蛋白质-蛋白质相互作用 电子受体将提供对蛋白质-蛋白质过程的洞察 识别是广泛的生物现象所共有的。长 Range ET是生物能量现象的中心过程，如 呼吸作用和中间代谢的某些反应。 长程间质蛋白作用机制和途径的研究进展 ET将使我们更好地理解这些基本过程 分子水平。

DESCRIPTION: The objective of this project is to define mechanisms of catalysis and electron transfer (ET) by selected quinoprotein dehydrogenases and their physiologic protein redox partners. These proteins are being used to develop and test hypotheses concerning (I) the roles of protein-bound quinone cofactors in catalysis and ET, (ii) mechanisms of long range interprotein ET reactions, and (iii) factors which stabilize the specific interactions between soluble proteins that facilitate intermolecular ET. study of physiologic ET reactions has for the most part been limited to integral membrane proteins for which structural information is difficult to obtain. Quinoprotein dehydrogenases are soluble and have two relatively unique and interesting properties. They utilize enzyme-bound quinones as prosthetic groups, and for electron acceptors they use other proteins rather than O2 or pyridine nucleotides. We are characterizing catalytic reaction mechanisms of the quinoproteins, developing kinetic models for their ET reactions, and determining crystal structures of these proteins free and in complex with physiologic redox partners. This allows us to correlate structural information with the results of our studies. A major aim of this proposal is to use site-directed mutagenesis to test hypothesis which have been developed concerning mechanisms of catalysis, protein-protein interaction and long range ET. Elucidation of factors which influence specific protein-protein interactions between quinoproteins and their electron acceptors will provide insight into the process of protein-protein recognition which is common to a wide range of biologic phenomena. Long range ET is a process which is central to bioenergetic phenomena such as respiration and certain reactions of intermediary metabolism. Characterization of the mechanisms and pathways of long range interprotein ET will allow us to better understand these fundamental processes at the molecular level.