Askerka Mikhail, Wang Jimin, Vinyard David J, Brudvig Gary W, Batista Victor S
Department of Chemistry and ‡Department of Molecular Biophysics and Biochemistry, Yale University , New Haven, Connecticut 06520-8107, United States.
Biochemistry. 2016 Feb 23;55(7):981-4. doi: 10.1021/acs.biochem.6b00041. Epub 2016 Feb 9.
The oxygen-evolving complex (OEC) of photosystem II has been studied in the S3 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 S3 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 S2 → S3 transition through a carousel rearrangement around Mn4, inspired by studies of ammonia binding.
通过电子顺磁共振、扩展X射线吸收精细结构（EXAFS）和飞秒X射线衍射（XRD）对光系统II的析氧复合物（OEC）在S3状态下进行了研究。然而，S3状态下OEC的实际结构尚未确定。在此，我们应用量子力学/分子力学混合方法，提出了一个与EXAFS和XRD一致的结构模型。受氨结合研究的启发，该模型支持在S2→S3转变过程中，水配体通过围绕Mn4的旋转木马重排与簇结合。
