STRUCTURAL STUDIES OF THE REACTION CENTER FROM RHODOBACTER SPHAEROIDES

本子项目是利用由NIH/NCRR资助的中心赠款提供的资源的众多研究子项目之一。子项目和研究者（PI）可能已经从另一个NIH来源获得了主要资金，因此可以在其他CRISP条目中表示。列出的机构是中心的，不一定是研究者的机构。光合反应中心（RC）是一种完整的膜蛋白-色素复合物，它执行光诱导电子从细菌叶绿素二聚体(D)转移到两个醌分子QA和QB。RC与另一种含有色素的完整膜蛋白形成复合体，称为光收集复合体（LH1），其主要功能是收集光并将能量传递给RC和光氧化d。此外，一个14千顿的水溶性细胞色素c2会短暂地与RC结合并重新还原d。我们在SSRL的持续工作将集中在RC的三个结构功能方面：1)。与其他蛋白络合的RC结构的测定：a)。RC和光收获蛋白（LH1）， b).影响RC与cytc2结合和电子转移的突变体。2）. 影响RC中质子和电子转移事件的突变体结构的测定。3)。以增强分辨率确定参与电荷分离的中间体结构，包括D+QA-， D+QB-和双基中间体状态DQA-QB-。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Photosynthetic reaction centers (RC) are integral membrane protein-pigment complexes that perform light induced electron transfer from a bacteriochlorophyll dimer (D) to two quinone molecules QA and QB. The RC forms a complex with another pigment-containing integral membrane protein called the light-harvesting complex (LH1) whose primary function is to gather light and transfer this energy to the RC and photo-oxidize D. In addition, a 14-kilodalton water soluble-cytochrome c2 transiently binds to the RC and re-reduces D. Our ongoing work at SSRL will focus on three structure-function aspects of the RC: 1). Determination of the structure of the RC complexed with other proteins: a). RC and light harvesting protein (LH1), and b). mutants that affect the binding and electron transfer between RC with cyt c2 . 2). Determination of the structures of mutants that affect proton and electron transfer events in the RC. 3). Determination of the structures at an enhanced resolution of intermediates that are involved in the charge separation, including D+QA-, D+QB-, and the biradical intermediate state DQA-QB-.