Primary Electron Transfer Processes in Photosynthetic Bacterial Reaction Centers

小行星9405248 光合生物的反应中心（RC）是膜结合的色素-蛋白质复合物，在其中光能通过一系列快速和高度特异性的电子转移反应转化为化学能。整个过程以基本上统一的量子产率跨RC（并且因此跨膜）分离电荷。这项研究的最终目标是在分子水平上全面了解这一过程。为此，跨越飞秒到毫秒时间尺度的瞬态吸收光谱测量以及其他光谱技术将用于直接识别和研究电荷分离的中间状态及其形成和衰减的速率。这些研究将在野生型RC和多种突变型RC上进行，其中使用分子生物学技术改变一个或多个氨基酸。 %%% 这项研究具有超越光合作用研究的广泛意义。这些研究将影响对电子转移的一般理解。RC在许多方面是一个微型实验室，用于调查这一基本过程，考虑到RC结构的知识以及详细操纵和调查电荷分离事件的能力。这些研究还将解决蛋白质在能量转换过程中的作用，从而影响氨基酸和嵌入的辅因子之间的相互作用如何影响生物事件的重要领域。这项工作还为理解和开发捕获和储存太阳能的有效机制奠定了基础。 因此，这项研究不仅对于理解地球上生命所必需的自然过程很重要，而且对于在生物学和化学的广泛重要领域获得进一步的知识也很重要。 ***

9405248 Holten The reaction center (RC) of photosynthetic organisms is the membrane bound pigment-protein complex within which light energy is converted into chemical energy via a series of fast and highly specific electron transfer reactions. The overall process separates charge across the RC (and hence across the membrane) with an essentially unity quantum yield. The ultimate goal of this research 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 techniques will be used to directly identify and study the intermediate states of charge separation and the rates 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 using the techniques of molecular biology. %%% This research has broad implications that transcend photosynthesis reasch. The investigations will impact on the general understanding of electron transfer. The RC is in many respects a mini-laboratory for the investigation of this fundamental process in view of knowledge of the structure of the RC and the ability to manipulate and investigate the charge separation events in detail. The studies will also address the role of the protein in the energy conversion process, and thus will impact on the important area of how the interactions between amino acids and the imbedded cofactors influence biological events. This work additionally forms the foundation for understanding and developing efficient mechanisms for the capture and storage of solar energy. Hence, this research is important not only for understanding a natural process essential for life on earth, but also for gaining further knowledge in areas of broad importance in biologyand chemistry. ***