QUINONE BINDING SITES IN BACTERIAL REACTION CENTERS

细菌反应中心的醌结合位点

• 批准号: 2022288
• 负责人: MELVIN Y OKAMURA
• 金额: $ 20.16万
• 依托单位: UNIVERSITY OF CALIFORNIA, SAN DIEGO
• 依托单位国家: 美国
• 财政年份: 1989
• 资助国家: 美国
• 起止时间: 1989-04-01 至 1998-11-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2022288
• 关键词: Rhodopseudomonas; X ray crystallography; bioenergetics; chemical binding; chemical kinetics; computer simulation; electron transport; hydrogen transport; ionic bond; membrane proteins; photosynthetic reaction centers; protein structure function; quinones; site directed mutagenesis; spectrometry

The bacterial reaction center (RC) is the membrane protein responsible for the initial light induced electron and proton transfer reactions responsible for conversion of light energy into chemical energy. A key component in this process is the bound quinone, Q/B which undergoes reaction, Q/B + 2e minus + 2 H+ equals Q/B H/2, coupling electron transfer with proton uptake from solution. This reaction is the first step in the proton pump that drives protons across the membrane using energy derived from electron transfer. The approach in this study is to use site directed mutagenesis to genetically modify key residues in the RC structure near the Q/B site and the to analyze the results of these changes by kinetic measurements, spectroscopic techniques and computational methods. The mutations are designed to identify the pathway of proton transfer and to test the role of electrostatic interactions and internal water molecules on proton transfer. Spectroscopic studies on native RCs and mutants will be conducted to identify key intermediates, such as the protonated semiquinone, in electron and proton transfer reactions. The ultimate goal of this project is to understand the structural basis for proton transfer into biological membranes, electron transfer between quinone molecules and the coupling between proton and electron transfer. These basic processes are responsible for energy conversion in many biological systems, such as mitochondria. The understanding of the structural basis for these processes can lead to elucidation of genetic defects that lead to metabolic deficiency and disease.

细菌反应中心（RC）是膜蛋白，负责 最初的光诱导电子和质子转移反应 负责将光能转化为化学能。 一把钥匙 该过程中的成分是结合醌，Q/B，它经历了 反应，Q/B + 2e 减去 + 2 H+ 等于 Q/B H/2，耦合电子转移 从溶液中吸收质子。 这个反应是第一步 利用产生的能量驱动质子穿过膜的质子泵 来自电子转移。 本研究的方法是使用站点 定向诱变对 RC 中的关键残基进行遗传修饰 Q/B 站点附近的结构并分析这些结果 通过动力学测量、光谱技术和 计算方法。 突变旨在识别途径 质子转移并测试静电相互作用的作用和 内部水分子进行质子转移。 光谱研究 将进行天然 RC 和突变体以确定关键中间体， 例如电子和质子转移中的质子化半醌 反应。 该项目的最终目标是了解 质子转移到生物膜、电子的结构基础 醌分子之间的转移以及质子和质子之间的耦合 电子转移。 这些基本过程负责能量 许多生物系统中的转化，例如线粒体。 这 了解这些过程的结构基础可以导致 阐明导致代谢缺陷的遗传缺陷和 疾病。