Water splitting in PS II: biophysical studies

描述(申请人提供)：金属在生物催化中扮演着重要的角色：超过20%的酶在其催化中心含有金属。地球上最重要的生物金属催化反应之一是光系统II中的放氧复合体催化的水的氧化和氧气的释放。光系统II产生大气中的所有氧气，人类和动物通过呼吸提供能量。光系统II是嵌入在光合膜中的一种大型膜蛋白复合体，由17种蛋白质组成，50多种辅因子与这些蛋白质结合，完成捕光、电荷分离和水氧化等复杂反应。 该项目的主要目标是在原子分辨率下确定光系统II的结构，并阐明四核锰团簇氧化水的机理。 确定了结晶过程的物理化学参数，改进后的晶体将作为X射线结晶学测定光系统II结构的基础。利用不同的电子顺磁共振(EPR)技术对光系统II的单晶进行光谱研究，研究与水氧化有关的辅因子的电子结构。 最终的目标是利用结构和功能研究来揭开光系统II的水氧化机制的秘密。

DESCRIPTION (provided by applicant): Metals play an important role in biocatalysis: more than 20% of all enzymes contain metals in their catalytic centers. One of the most important biometal-catalyzed reactions on earth is the oxidation of water and the release of oxygen catalyzed by the oxygen-evolving complex in Photosystem II. Photosystem II produces all the oxygen in the atmosphere, which humans and animals use for their energy supply by respiration. Photosystem II is a large membrane protein complex embedded in the photosynthetic membrane consisting of 17 proteins to which more than 50 cofactors are bound to perform the complex reactions of light capturing, charge separation and water oxidation. This project has as its main goal the determination of the structure of Photosystem II at atomic resolution and the elucidation of the mechanism of water oxidation by the tetra-nuclear manganese cluster. The physical-chemical parameters of the crystallization process will be determined and the improved crystals will serve as the basis for the determination of the structure of Photosystem II by X-ray crystallography. The electronic structure of the cofactors that are involved in water oxidation will be investigated by spectroscopic investigations using different Electron Paramagnetic Resonance (EPR) techniques on single crystals of Photosystem II. The final goal is to use the structural and functional investigations to unravel the secrets of the mechanism of water oxidation by Photosystem II.