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: 9723661
• 负责人: John Golbeck
• 金额: $ 11.5万
• 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: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9723661&HistoricalAwards=false
• 关键词: Resolution; Reconstitution; Photosystem; Cyanobacteria; Higher

9723661 Golbeck. The aim of this work is to understand the molecular mechanisms which lead to the high quantum yield and high thermodynamic efficiency of light-to-chemical free energy conversion in Type I (iron-sulfur) photosynthetic reaction centers. To achieve this level of understanding about the intermediate electron acceptor A1, the ligands which bind the phylloquinone whether one or both of the phylloquinone pathways is utilized in electron transfer, and if it is possible to manipulate the amino acids so that quinones with altered redox potentials can be exchanged into the site, must be determined. The issues regarding the mutants of FA and FB include using substituted aryl thiolates to modify the midpoint potentials of the iron-sulfur clusters, using thiolated viologen derivatives to function as kinetic probes of electron transfer, and using viologen derivatives with different tether lengths to investigate the effect of distance on electron transfer rate. The work on the low molecular mass polypeptides PsaE through PsaM includes measurements of a possible electron transfer pathway through PsaE, and whether the PsaF, PsaI, PsaJ, PsaK or PsaM provide links for energy spillover from light absorbed by phycobilisomes. The overall goal of this work is to study the structure, function and organization of the photosystem I reaction center in cyanobacteria and plants. A combination of organic chemical synthesis, site-directed mutagenesis and spectroscopic characterization including time-resolved optical and EPR, will be employed to probe these issues. ***

9723661 Golbeck。本工作的目的是了解导致I型（铁硫）光合反应中心光-化学自由能转换的高量子产率和高热力学效率的分子机制。为了达到对中间电子受体A1的这种程度的理解，必须确定与叶绿醌结合的配体，无论叶绿醌的一种或两种途径在电子转移中被利用，以及是否有可能操纵氨基酸以使具有改变的氧化还原电位的醌可以交换到该位点。关于FA和FB突变体的研究问题包括：利用取代芳基硫酸酯修饰铁硫簇的中点电位；利用巯基硫代紫嘌呤衍生物作为电子转移的动力学探针；利用不同系链长度的紫嘌呤衍生物研究距离对电子转移速率的影响。通过PsaM研究低分子质量多肽PsaE的工作包括测量通过PsaE的可能的电子转移途径，以及PsaF、PsaI、PsaJ、PsaK或PsaM是否为藻胆异构体吸收光的能量溢出提供了联系。本工作的总体目标是研究蓝藻和植物光系统I反应中心的结构、功能和组织。将采用有机化学合成、定点诱变和光谱表征（包括时间分辨光学和EPR）的结合来探讨这些问题。＊＊＊