STRUCTURAL STUDIES OF THE PHOTOSYNTHETIC REACTION CENTER FROM R SPHAEROIDES

这个子项目是许多研究子项目中的一个 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得了主要资金， 因此可以在其他CRISP条目中表示。所列机构为 研究中心，而研究中心不一定是研究者所在的机构。 反应中心（RC）是一种完整的膜蛋白，经历光诱导的电子转移反应，这是将光转化为化学能的主要步骤。在光激发下，电子从细菌叶绿素二聚体（D）的激发态通过中间受体分子转移到两个醌分子QA和QB。RC与另一种含有色素的膜蛋白复合，即捕光复合物（LH 1），它收集光能并将光能转移到RC，从而产生光氧化的D。随后，14千道尔顿的水溶性细胞色素c2瞬时结合RC并重新还原D。我们在SSRL正在进行的工作将集中在RC的三个结构-功能方面：1）。确定RC-金属络合物和突变体的结构，影响RC中的质子和电子转移事件。2）。电荷分离过程中中间态结构的确定。 3）。确定与伴侣蛋白复合的RC的结构：a）. RC和捕光蛋白（LH 1），和B）。影响RC与cyt c2之间结合和电子转移的突变体。

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. The Reaction Center (RC), an integral membrane protein, undergoes light induced electron transfer reactions which are the primary steps in converting light into chemical energy. Upon excitation by light, electron transfer occurs from the excited state of a bacteriochlorophyll dimer (D) through intermediate acceptor molecules to two quinone molecules, QA and QB. The RC complexes with another pigment-containing integral membrane protein, the light-harvesting complex (LH1) which gathers and transfers light energy to the RC resulting in photo-oxidized D. Subsequently, 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 structures of RC-metal complexes and mutants that affect proton and electron transfer events in the RC. 2). Determination of the structures of intermediate states involved in the charge separation. 3). Determination of the structure of the RC complexed with partner proteins: a). RC and light harvesting protein (LH1), and b). Mutants that affect the binding and electron transfer between RC with cyt c2.