QUINONE BINDING SITES IN BACTERIAL REACTION CENTERS

细菌反应中心(RC)是负责 初始光诱导的电子和质子转移反应 负责将光能转化为化学能。一把钥匙 这个过程中的成分是结合的苯二酚，Q/B 反应，Q/B+2E减去+2H+等于Q/B H/2，耦合电子转移 从溶液中吸收质子。这一反应是 质子泵，利用从膜中获得的能量驱动质子穿过膜 来自电子转移。本研究的方法是使用SITE 定向突变以遗传修饰RC中的关键残基 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。这些突变被设计用来识别这条途径 并测试静电相互作用的作用 内部水分子对质子转移的影响。光谱学研究 将进行原生RCS和突变体以确定关键中间体， 例如质子化的半喹酮，在电子和质子转移中 反应。本项目的最终目标是了解 质子转移到生物膜的结构基础，电子 对苯二酚分子间的转移及质子与苯二酚的耦合 电子转移。这些基本的过程负责能量 在许多生物系统中的转换，如线粒体。这个 对这些过程的结构基础的理解可以导致 阐明导致代谢缺陷的遗传缺陷和 疾病。

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.