Mechanism and Macromolecular Organization in Photosynthetic Reaction Centers and Membranes

这一建议要求继续支持生物物理学研究的电荷分离和重组步骤的光合反应中心（RC）和更高层次的组织光合膜的机制。我们工作的一个重要组成部分是开发新的实验和理论方法，这些方法可以在科学和生物技术的其他领域产生广泛的影响。了解光合系统中的能量和电子转移机制已被证明是这种发展和培训科学家的一个非常肥沃的领域。在这个项目中，将在以下与反应中心电荷分离机制有关的具体领域进行研究：（i）使用共振斯塔克光谱法确定控制由功能侧单体细菌叶绿素激发引发的替代电子转移途径的基本参数;（ii）将共振斯塔克方法应用于通过设计RC而产生的其他路径;（三）测量特殊对三重态衰变的激活能和磁场依赖性，以确定初级的能量学。RC突变体中的电荷分离;（iv）旁观者染料分子在功能组分附近的附着，以探测第一电子转移步骤期间电荷运动的动力学;（v）支持双层中光合膜中组分的组织。通过整合这一系列的方法，我们的理解的初始电子转移的机制和单向电子转移的相关现象，可以提前，并在复杂的生物组件的结构-功能关系的大背景下。

This proposal requests continued support for biophysical studies of the mechanism of the charge separation and recombination steps in photosynthetic reaction centers (RCs) and the higher-order organization of photosynthetic membranes. An important part of our work involves the development of new experimental and theoretical methods that can have a broad impact in other areas of science and biotechnology. Understanding the mechanisms of energy and electron transfer in photosynthetic systems has proven to be an exceptionally fertile area for such developments and for training scientists. In this project, research will be performed in the following specific areas that relate to the mechanism of charge separation in the reaction center: (i) determination of the fundamental parameters that control alternative electron transfer pathways initiated by excitation of the monomeric bacteriochlorophyll on the functional side using resonance Stark spectroscopy; (ii) application of the resonance Stark method to other pathways created by engineering the RC; (iii) measurements of the activation energy and magnetic field dependence of the decay of the special pair triplet state to determine the energetics of the primary charge separation in RC mutants; (iv) attachment of spectator dye molecules near the functional components to probe the dynamics of charge motion during the first electron transfer step(s); (v) organization of components in the photosynthetic membrane in supported bilayers. By integrating this range of approaches, our understanding of the mechanism of initial electron transfer and the related phenomenon of unidirectional electron transfer can be advanced and brought into the larger context of structure-function relationships in complex biological assemblies.