Primary Electron Transfer Processes in Photosynthetic Bacterial Reaction Centers

光合细菌反应中心的初级电子转移过程

• 批准号: 9205019
• 负责人: Dewey Holten
• 金额: $ 24.5万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-01 至 1995-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9205019&HistoricalAwards=false
• 关键词: Primary; Electron; Transfer; Processes; Photosynthetic

The bacterial reaction center (RC) is the membrane bound pigment- protein complex within which light energy is converted into chemical energy. This photoconversion process occurs via a series of fast and highly specific electron transfer reactions that separate charge across the RC (and thus across the membrane) with unity quantum yield. The ultimate goal of this work is to arrive at a comprehensive understanding of this process at a molecular level. To this end, transient absorption spectroscopic measurements spanning the femtosecond to millisecond timescales as well as other spectroscopic studies will be carried out to directly identify and study the intermediate states of charge separation and the rates and yields of their formation and decay. These studies will be carried out on both wild-type RCs and a wide variety of mutant RCs in which one or more amino acids are changed. Numerous unresolved issues regarding the involvement of specific chromophores in the pathway of electron transfer, and the selectivity (or directionality) of these reactions will be addressed. Factors underlying the balancing of the competition between the forward electron transfer reactions and the deactivating (or back) reactions will be investigated. These studies will also address the role of the protein in the charge separation process, both at the level of specific amino acids and at a more global level. The results of this work will be compared with predictions from various theoretical models for electron transfer and, indeed, will likely form the basis for further theoretical developments. %%% The conversion of light energy into chemical energy is essential for life on earth. Detailed studies of the mechanism of this energy conversion process are essential not only for increasing the understanding of one of the most important biological processes, but also as a foundation for devising biomimetic systems for solar energy conversion. The proposed studies will provide diverse information that is critical for elucidating the molecular mechanisms by which the reaction center functions. The studies also will advance knowledge of the factors that control electron transfer, which is one of the most fundamental processes in biology and chemistry. Additionally, the research will provide detailed new information on the effects of pigment- protein interactions and protein dynamics on the energetics, rates and mechanisms of biological processes. Hence, the proposed research should have a very positive impact on our fundamental understanding of photosynthesis and on the applied aspects of photosynthetic energy conversion.

细菌反应中心（RC）是膜结合色素- 蛋白质复合物，其中光能被转化为 化学能 这种光转换过程通过 一系列快速、高特异性的电子转移反应 在RC上分离电荷（从而在 膜）具有单位量子产率。 这个项目的最终目标 我们的工作是全面了解这一点， 在分子水平上进行。 为此，瞬态吸收 光谱测量跨越飞秒， 毫秒时间尺度以及其他光谱研究 将进行直接识别和研究 电荷分离的中间状态以及速率和产率 它们的形成和衰变。 这些研究将在 在野生型RC和多种突变型RC上， 一个或多个氨基酸被改变。 许多悬而未决的问题 关于特定发色团参与的途径 电子转移的选择性（或方向性） 这些反应将得到解决。 造成这一现象的因素 平衡前向电子之间的竞争 转移反应和失活（或反）反应将 追究 这些研究还将探讨 蛋白质在电荷分离过程中，无论是在水平 具体的氨基酸和在更全球的水平。 的结果 这项工作将与各种预测进行比较， 电子转移的理论模型，事实上， 为进一步的理论发展奠定了基础。 %%% 光能转化为化学能是必不可少的 地球上的生命。 详细研究了这一机制， 能源转换过程不仅对增加 对人类最重要的生物学现象之一 过程，但也作为设计仿生系统的基础 用于太阳能转换。 拟议的研究将提供 不同的信息，这是至关重要的阐明 反应中心发挥作用的分子机制。 的 研究还将进一步了解控制这些疾病的因素， 电子转移是最基本的过程之一 在生物学和化学上。 此外，研究将 提供关于色素影响的详细新信息- 蛋白质相互作用和蛋白质动力学在能量学上， 生物过程的速率和机制。 所以 这项研究将对我们的未来产生积极的影响。 对光合作用的基本认识及其应用 光合作用能量转换方面。