S0-State Model of the Oxygen-Evolving Complex of Photosystem II
S0-State Model of the Oxygen-Evolving Complex of Photosystem II
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DOI：
10.1021/bi401214v
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发表时间：
2013-11-05
期刊：
影响因子：
2.9
通讯作者：
Batista, Victor S.
中科院分区：
文献类型：
--
作者：
Pal, Rhitankar;Negre, Christian F. A.;Batista, Victor S.
光系统II的出氧络合物（OEC）的S-0 -> S-1转变是水分解Kok循环中最不为人所知的步骤之一。我们引入了与扩展x射线吸收精细结构光谱和x射线衍射数据一致的S-0态量子力学/分子力学（QM/MM）模型。结合S-1态的QM/MM模型，我们研究了S-0 -> S-1跃迁过程中发生的质子耦合电子转移（PCET）过程，其中Mn中心的氧化和mu-氧桥的去质子化导致OEC中显著的重排。提出了一个氢键网络，将D1-D61残基与mn结合的水分子连接起来，以促进PCET机制。
The S-0 -> S-1 transition of the oxygen-evolving complex (OEC) of photosystem II is one of the least understood steps in the Kok cycle of water splitting. We introduce a quantum mechanics/molecular mechanics (QM/MM) model of the S-0 state that is consistent with extended X-ray absorption fine structure spectroscopy and X-ray diffraction data. In conjunction with the QM/MM model of the S-1 state, we address the proton-coupled electron-transfer (PCET) process that occurs during the S-0 -> S-1 transition, where oxidation of a Mn center and deprotonation of a mu-oxo bridge lead to a significant rearrangement in the OEC. A hydrogen bonding network, linking the D1-D61 residue to a Mn-bound water molecule, is proposed to facilitate the PCET mechanism.