Resolution and Reconstitution of Photosystem I in Cyanobacteria and Higher Plants: Molecular Biological and Physicochemical Studies

蓝藻和高等植物中光系统 I 的解析和重建：分子生物学和物理化学研究

• 批准号: 0117079
• 负责人: John Golbeck
• 金额: $ 64.5万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0117079&HistoricalAwards=false
• 关键词: Resolution; Reconstitution; Photosystem; Cyanobacteria; Higher

This research program aims at understanding the structure,function and organization of the Photosystem I reaction center in cyanobacteria and green plants.The advances made so far include a biological method to introduce alternative quinones into the A1site,an experimental approach to determine whether electron transfer is uni-or bi-directional among the symmetrically-located electron transfer cofactors,and a determination of the 3-dimensional NMR solution structure of unbound PsaC.This,combined with newly-available structural information about the 3-dimensional spatial arrangement of atoms from X-ray crystallography and the electron spin density distribution in cofactors from magnetic resonance spectroscopy,has opened new avenues for research in PS I. One is the effect of biological incorporation of alternative quinones into the A1 site for studies of the effect of Gibbs free energy changes on rates of forward and backward electron transfer, and for studies of the electron density distribution within the A1 - acceptor. Another is the protein-protein interactions at the molecular level between the PsaA,PsaB, PsaC,and PsaD subunits,and focuses especially on the changes in secondary structure that take place when PsaC docks with its protein partners in PS I.The goal is to determine the dynamic interactions that occur among these to produce a functional PS I complex.These studies promise to have an impact on the understanding of protein factors responsible for conferring redox properties to organic cofactors and on the understanding of protein-protein interactions in the assembly of multi-component,membrane-bound complexes.Hence,this work should have relevance well beyond the realm of oxygenic photosynthesis

本研究计划旨在了解蓝细菌和绿色植物光系统I反应中心的结构、功能和组织，迄今取得的进展包括将替代醌类引入A1位点的生物学方法，确定电子传递辅因子之间电子传递是单向还是双向的实验方法，以及未结合PsaC的三维NMR溶液结构的确定。这与来自X射线晶体学的关于原子的三维空间排列的新可用结构信息和来自磁共振光谱学的辅因子中的电子自旋密度分布相结合，为PS I的研究开辟了新的途径 一个是生物纳入替代醌到A1网站的吉布斯自由能变化的影响的研究，对正向和反向电子转移速率的影响，并为A1 -受体内的电子密度分布的研究。 另一个是PsaA、PsaB、PsaC和PsaD亚基之间在分子水平上的蛋白质-蛋白质相互作用，并特别关注当PsaC与PS I中的蛋白质伴侣对接时发生的二级结构变化。目标是确定这些之间发生的动态相互作用，以产生功能性PS I复合物。这些研究有望对理解负责PS I的蛋白质因素产生影响。赋予有机辅因子氧化还原特性，以及理解多组分膜结合复合物组装中蛋白质-蛋白质相互作用。因此，这项工作的相关性应远远超出产氧光合作用的范围