STRUCTURE/FUNCTION & BIOSYNTHESIS OF RESPIRATORY ENZYMES

描述：本项目的目标是确定 通过选择的醌蛋白酶的催化和电子转移（ET） 和它们的生理蛋白质氧化还原伴侣。 这些蛋白质被用来 开发和测试假设有关（一）蛋白质结合的作用， 醌辅因子在催化和ET，（ii）机制的远程 蛋白质间ET反应，和（iii）稳定特异性 促进分子间ET的可溶性蛋白质之间的相互作用。 生理性ET反应的研究大部分限于 整合膜蛋白，其结构信息难以 获得。 醌蛋白水解酶是可溶性的，具有两个相对分子质量。 独特和有趣的属性。 它们利用酶结合的醌作为 辅基，而对于电子受体，它们使用其他蛋白质， 比氧气或吡啶核苷酸更好。 我们在描述催化反应 机制的醌蛋白，发展动力学模型，其ET 反应，并确定这些蛋白质的晶体结构自由和 与生理氧化还原伴侣复合。 这使我们能够将 结构信息与我们的研究结果。 其主要目的是 建议是使用定点诱变来测试假设， 在催化、蛋白质-蛋白质 相互作用和远程ET。 影响因素分析 醌蛋白之间的特异性蛋白质-蛋白质相互作用及其 电子受体将提供深入了解蛋白质-蛋白质 这是一种普遍的生物现象。 长 范围ET是一个过程，它是生物能现象的核心， 呼吸和某些中间代谢反应。 长距离蛋白间作用机制和途径的研究进展 ET将使我们能够更好地了解这些基本过程， 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.