S3 State of the O2-Evolving Complex of Photosystem II: Insights from QM/MM, EXAFS, and Femtosecond X-ray Diffraction
S3 State of the O2-Evolving Complex of Photosystem II: Insights from QM/MM, EXAFS, and Femtosecond X-ray Diffraction
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DOI：
10.1021/acs.biochem.6b00041
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发表时间：
2016-02-23
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：
Askerka, Mikhail;Wang, Jimin;Batista, Victor S.
用电子顺磁共振、扩展X射线吸收精细结构和飞秒X射线衍射研究了S-3态光系统II的放氧复合体。然而，S-3状态的OEC的实际结构尚未确定。在这里，我们应用量子力学/分子力学的混合方法，提出了一个与EXAFS和X射线衍射法相一致的结构模型。受氨结合研究的启发，该模型支持在S-2-S-3转变中通过围绕Mn4的旋转木马重排将水配体结合到团簇上。
The oxygen-evolving complex (OEC) of photosystem II has been studied in the S-3 state by electron paramagnetic resonance, extended X-ray absorption fine structure (EXAFS), and femtosecond X-ray diffraction (XRD). However, the actual structure of the OEC in the S-3 state has yet to be established. Here, we apply hybrid quantum mechanics/molecular mechanics methods and propose a structural model that is consistent with EXAFS and XRD. The model supports binding of water ligands to the cluster in the S-2 -> S-3 transition through a carousel rearrangement around Mn4, inspired by studies of ammonia binding.