STRUCTURE-FUNTION RELATIONS IN PHOTOSYNTHEITIC SYSTEM

光合成系统中的结构-功能关系

• 批准号: 3468430
• 负责人: JOANN C WILLIAMS
• 金额: $ 10.19万
• 依托单位: ARIZONA STATE UNIVERSITY-TEMPE CAMPUS
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-07-01 至 1996-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3468430
• 关键词: X ray crystallography; atomic absorption spectrometry; bacterial pigment; bioenergetics; electron spin resonance spectroscopy; electron transport; electroporation; gene deletion mutation; iron compounds; ligands; molecular cloning; molecular site; operon; photoactivation; photosynthesis; photosynthetic bacteria; plasmids; protein sequence; protein structure function; quinones; restriction mapping; site directed mutagenesis; transposon /insertion element

In a broad sense, the objectives of this research are to understand biological processes on a molecular level, and to further expand the range of molecular genetics techniques available for exploring such questions. The specific problem addressed in this proposal concerns the mechanism of photochemical energy conversion in bacteria. The site of the primary photochemistry is an integral membrane pigment-protein complex called the reaction center. Our goal is to extend our understanding of the role of specific amino acid residues and cofactors in the function of the reaction center. The methodologies used in this proposal combine the ability to alter proteins in specific ways by molecular genetics and the elucidation of structural and functional changes by an interdisciplinary range of biochemical and spectroscopic techniques. An investigation of the effect of systematic alterations of amino acid residues by site-directed mutagenesis of the reaction center genes is planned. Molecular genetic techniques will be used to develop a system in the purple bacterium, Rhodobacter sphaeroides, in which any amino acid residue of the reaction center can be changed and the resulting mutation analyzed with a minimum of difficulty. The role of the non-heme iron atom in the reaction center will be addressed by characterizing a set of mutant reaction centers containing changes in the ligands to the iron, with regard to the specificity of the metal binding site, the electronic environment of the iron, electron transfer rates involving nearby cofactors, and the three dimensional structures. Construction and analysis of mutations in other residues that are highly conserved in related proteins from other photosynthetic organisms are planned. Some of the findings and methodologies are expected to be relevant to the binding of metals in other proteins, the structure of membrane proteins, and the process of electron transfer, most notably in the respiratory chain in mitochondria.

从广义上讲，这项研究的目标是了解 分子水平的生物过程，并进一步扩大范围 可用于探索此类问题的分子遗传学技术。 本提案中解决的具体问题涉及 细菌中的光化学转化。 主要的地点 光化学是一种整体膜色素 - 蛋白质复合物，称为 反应中心。 我们的目标是扩展我们对 反应功能的特定氨基酸残基和辅因子 中心。 该提案中使用的方法结合了 通过分子遗传学和阐明以特定方式改变蛋白质 通过跨学科范围的结构和功能变化 生化和光谱技术。 对效果的调查 通过现场定向对氨基酸残基的系统改变 计划了反应中心基因的诱变。 分子遗传 技术将用于开发紫色细菌中的系统， Rhodobacter sphaeroides，其中任何反应的氨基酸残基 可以更改中心，并以最小的限度分析所得突变 困难。 非血红素铁原子在反应中心的作用 将通过表征一组突变反应中心来解决 关于配体的变化与铁的变化有关 金属结合位点的特异性，即电子环境 铁，涉及附近辅助因子的电子传输速率，三个 尺寸结构。 其他突变的构建和分析 在其他其他相关蛋白质中高度保守的残基 计划了光合生物。 一些发现和 预计方法与其他金属的结合有关 蛋白质，膜蛋白的结构和电子的过程 转移，最著名的是在线粒体的呼吸链中。