The Mechanism of Water Splitting and Oxygen Evolution in Photosynthesis

水氧化成分子氧是一个特征 与高等植物光合作用有关的反应， 蓝藻 光量子产生的激发 光系统导致电子一次一个地转移 直到从两个水分子中移走四个电子， 产生O2。 绍尔博士和克莱因博士正在研究 中间体参与这种电子转移， 储存产生O2所需的氧化当量。 锰与水分解酶有关， 正在使用X射线吸收光谱来确定 锰周围的氧化态、连接和局部结构。 与使用EPR光谱的研究一起，他们的结果 证实了Mn氧化态的直接参与 水分解过程的变化。 这项建议旨在 进一步表征Mn原子四重态的结构 参与，必要的辅因子，抑制剂和蛋白质 配体通过使用X射线吸收光谱， 电子-核和电子-电子双共振 光谱学 他们希望学习，最重要的是， 水被掺入到水分解酶中 在最终形成和释放O2之前。 知识 这一过程将是最有用的发展人工 利用太阳能将水转化为 分子氧和氢燃料。

The oxidation of water to molecular oxygen is a characteristic reaction associated with photosynthesis in higher plants and cyanobacteria. Light quanta producing excitation of the photosystem results in the transfer of electrons one at a time until four electrons are removed from two water molecules to produce O2. Drs. Sauer and Klein are investing the chemical intermediates involved in this transfer of electrons and in the storing of the oxidizing equivalents needed to yield O2. Manganese is involved in the water-splitting enzyme, and they are using X-ray absorption spectroscopy to determine the oxidation states, ligation and local structure around the Mn. Together with studies using EPR spectroscopy, their results have verified the direct participation of Mn oxidation state changes in the water-splitting process. This proposal aims to characterize further the structure of the quartet of Mn atoms involved, the essential cofactors, inhibitors and protein ligands through the use of X-ray absorption spectroscopy, electron-nuclear and electron-electron double resonance spectroscopies. They hope to learn, most importantly, how water becomes incorporated into the water-splitting enzyme prior to the final formation and release of O2. Knowledge of this process will be most useful in development artificial systems whereby solar energy can be used to convert water into molecular oxygen and hydrogen fuel.