REDOX AND ELECTRON-TRANSFER PROPERTIES OF FLAVODOXINS

黄素氧还蛋白的氧化还原和电子传递特性

• 批准号: 3290565
• 负责人: RICHARD P. SWENSON
• 金额: $ 17.19万
• 依托单位: OHIO STATE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-12-01 至 1995-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3290565
• 关键词: Clostridium; Desulfovibrio; Escherichia coli; Raman spectrometry; X ray crystallography; bacterial genetics; electron transport; enzyme mechanism; flavodoxin; flavoproteins; molecular cloning; nuclear magnetic resonance spectroscopy; oxidation reduction reaction; potentiometry; protein engineering; site directed mutagenesis

Flavoproteins constitute one of the largest groups of related proteins presently pathway including those involved in biosynthesis, biodegradation, and energy transduction in such diverse and essential life processes as oxidative-phosphorylation, photosynthesis, and nitrogen fixation. The number and variety of reactions involving flavoproteins attests to the remarkable versatility of the common flavin cofactor and suggests that the apoprotein exerts strict control over the redox and chemical properties of the bound flavin. Two overall objectives of our research are: 1) to learn how the specific interactions between apoprotein and flavin are involved in the control of the redox properties of the cofactor, and 2) to investigate how specific amino acid residues in the vicinity of the flavin cofactor influence and regulate electron transfer from the flavin to redox centers in other redox proteins. In this proposal we describe the continuation of a new approach to this fundamental problem in biology and life sciences. We have established a genetic system with which to apply recombinant DNA technology to engineer specific amino acid substitutions in the flavin binding site of the simplest and best characterized class of flavoprotein, the flavodoxin. The detailed X-ray crystal structures of four different flavodoxins have revealed, at the atomic level, specific features of flavin-protein interactions. Through protein engineering, we are able to determine which of these interaction are functionally critical and in what way. Fundamental properties under investigation include the unusually low redox potential of the flavin hydroquinone and the stabilization of the blue neutral semiquinone which results in the separation of these two redox couples in a way that is physiologically important as well as the structural features essential in electron transfer between the flavodoxin and donor/acceptor redox proteins such as certain cytochromes. This proposal describes a multifaceted approach in the generation of families of related flavodoxin proteins differing only in specific and well-defined regions of the flavin binding site and the application of a variety of spectroscopic approaches to assist us in establishing a correlation between these altered structural features and observed changes in the redox properties of the bound flavin cofactor.

黄素蛋白构成最大的相关蛋白质组之一 目前的途径，包括参与生物合成的途径， 如此多样化和必不可少的生物降解和能量转导 生命过程作为氧化磷酸化，光合作用和氮 固定。 涉及黄蛋白的反应的数量和种类 证明了普通黄素辅因子的显着多功能性和 表明载脂蛋白对氧化还原和 结合黄素的化学特性。 我们的两个总体目标 研究是：1）了解如何 载脂蛋白和黄素参与了氧化还原特性的控制 辅助因子和2）研究特定氨基酸残基 在黄素辅因子的附近影响和调节电子 从黄素转移到其他氧化还原蛋白中的氧化还原中心。 在 这项建议我们描述了一种新方法的延续 生物学和生命科学的基本问题。 我们已经建立了 将重组DNA技术应用于工程师的基因系统 特异性氨基酸取代的黄素结合位点 最简单，最佳特征的黄素蛋白，黄酮毒素。 四种不同类黄素毒素的详细X射线晶体结构具有 在原子水平上揭示了黄素 - 蛋白质的特定特征 互动。 通过蛋白质工程，我们能够确定 这些相互作用中的哪一个在功能上至关重要，并且以什么方式。 正在调查的基本属性包括异常低的 黄蛋白措施的氧化还原电势和稳定 蓝色中性半氨基酮，导致这两个分离 氧化还原夫妇以生理上重要的方式以及 黄酮毒素之间电子转移必不可少的结构特征 以及供体/受体氧化还原蛋白，例如某些细胞色素。 这 提案描述了一代家庭的多方面方法 仅在特定和 黄素结合位点的定义明确的区域和应用 各种光谱法方法，以帮助我们建立一个 这些改变的结构特征和观察到的相关性 结合黄素辅因子的氧化还原特性的变化。