STRUCTURE/FUNCTION & BIOSYNTHESIS OF RESPIRATORY ENZYMES

结构/功能

• 批准号: 6180259
• 负责人: VICTOR L DAVIDSON
• 金额: $ 24.26万
• 依托单位: UNIVERSITY OF MISSISSIPPI MED CTR
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-08-01 至 2001-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6180259
• 关键词: X ray crystallography; active sites; amine oxidoreductase; azurin; biophysics; chemical binding; chemical kinetics; cofactor; cytochrome c; electron nuclear double resonance spectroscopy; electron spin resonance spectroscopy; electron transport; enzyme biosynthesis; enzyme complex; enzyme mechanism; enzyme structure; enzyme substrate; nuclear magnetic resonance spectroscopy; protein protein interaction; quinones; respiratory enzyme; semiquinone; site directed mutagenesis; tryptophan

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.

描述：该项目的目标是定义机制 选定的醌蛋白脱氢酶的催化和电子转移 (ET) 及其生理蛋白质氧化还原伙伴。 这些蛋白质正在被使用 开发和测试有关 (I) 蛋白质结合的作用的假设 催化和 ET 中的醌辅因子，(ii) 长程机制 蛋白间 ET 反应，以及 (iii) 稳定特异性的因素 可溶性蛋白质之间的相互作用，促进分子间 ET。 生理 ET 反应的研究大部分局限于 难以获得其结构信息的整合膜蛋白 获得。 醌蛋白脱氢酶是可溶性的，并且具有两种相对 独特而有趣的属性。 他们利用酶结合醌作为 辅基，对于电子受体，他们使用其他蛋白质而不是 比 O2 或吡啶核苷酸。 我们正在表征催化反应 醌蛋白的机制，开发其 ET 的动力学模型 反应，并确定这些蛋白质的晶体结构 与生理氧化还原伙伴的复合物。 这使我们能够关联 结构信息与我们的研究结果。 此举的一个主要目的 建议使用定点诱变来检验假设 已开发出有关催化机制、蛋白质-蛋白质 相互作用和远距离ET。 影响因素的阐明 奎宁蛋白及其蛋白质之间的特异性蛋白质相互作用 电子受体将提供对蛋白质-蛋白质过程的深入了解 广泛的生物现象所共有的识别。 长的 ET 范围是生物能量现象的核心过程，例如 呼吸和中间代谢的某些反应。 长程蛋白间的机制和途径的表征 ET 将使我们能够更好地理解这些基本过程 分子水平。