Elucidation of the molecular mechanism of photosynthetic water oxidation by means of infrared spectroscopy

我们用光诱导傅里叶变换红外光谱研究了光合作用水氧化的分子机制，揭示了单个中间跃迁释放的质子数、跃迁效率、连接在Mn簇上的氨基酸的结构和作用、抑制剂对水氧化反应的影响以及外源蛋白质的调节机制。我们还用时间分辨红外光谱研究了水氧化反应中的质子耦合电子转移，得到了在S3→S0转变中质子在电子转移之前释放的实验证据，在这个转变中产生了分子氧。

We have investigated the molecular mechanism of photosynthetic water oxidation using light-induced Fourier transform infrared difference spectroscopy and revealed the number of protons released upon individual intermediate transitions, the efficiencies of transitions, the structures and the roles of amino-acids coupled to the Mn cluster, the effect of an inhibitor on water oxidation reactions, and the regulation mechanism by extrinsic proteins. We also studied proton-coupled electron transfer in the water oxidation reaction using time-resolved infrared spectroscopy and obtained experimental evidence that proton is released before the electron transfer in the S3→S0transition, in which molecular oxygen is evolved.