QUINONE BINDING SITES IN BACTERIAL REACTION CENTERS

细菌反应中心（RC）是负责 初始光诱导电子和质子转移反应 负责将光能转化为化学能。 一个关键 该过程中的一个组分是结合醌，Q/B，其经历 反应，Q/B +2 e-+ 2 H+= Q/B H/2，偶联电子转移 从溶液中吸收质子。 这个反应是第一步， 质子泵，其使用来自于质子泵的能量驱动质子穿过膜。 电子转移。 本研究的方法是使用现场 定向诱变以遗传修饰RC中的关键残基 结构附近的Q/B网站和分析这些结果 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 质子转移和测试静电相互作用的作用， 内部水分子质子转移。 的光谱研究 将进行天然RC和突变体以鉴定关键中间体， 例如质子化半醌，在电子和质子转移中 反应. 本项目的最终目标是了解 质子进入生物膜结构基础，电子 醌分子之间的转移和质子与 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化，如线粒体。 的 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， 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.