STRUCTURAL STUDIES OF THE PHOTOSYNTHETIC REACTION CENTER FROM R SPHAEROIDES

这个子项目是许多研究子项目中利用 资源由NIH/NCRR资助的中心拨款提供。子项目和 调查员(PI)可能从NIH的另一个来源获得了主要资金， 并因此可以在其他清晰的条目中表示。列出的机构是 该中心不一定是调查人员的机构。 反应中心(Rc)是一种完整的膜蛋白，它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苯二酚分子QA和QB。RC与另一种含有色素的整膜蛋白的复合物(LH1)，它聚集光能并将光能转移到RC，从而导致光氧化D。随后，14千道尔顿的水溶性细胞色素c2瞬时与RC结合，重新还原D。我们在SSRL进行的工作将集中在RC的三个结构功能方面：1)。测定影响RC中质子和电子转移事件的RC-金属络合物和突变体的结构。2)。电荷分离所涉及的中间态结构的确定。3)。与配对蛋白络合的RC的结构测定：a)。Rc和捕光蛋白(LH1)，以及b)。影响rc与cytc2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.