Necessity of structural rearrangements for O-O bond formation between O5 and W2 in photosystem Ⅱ

作者：Yu Guo; Biaobiao Zhang; Lars Kloo^*; Licheng Sun^*

来源：Journal of Energy Chemistry, 2021, 57(06): 436-442.

Numerous aspects of the water oxidation mechanism in photosystem Ⅱ have not been fully elucidated,especially the O-O bond formation pathway.However,a body of experimental evidences have identified the O5 and W2 ligands of the oxygen-evolving complex as the highly probable substrate candidates.In this work,we studied O-O bond formation between O5 and W2 based on the native Mn4 Ca cluster by density functional calculations.Structural rearrangements before the formation of the S4 state were found as a prerequisite for O-O bond formation between O5 and W2, regardless if the suggested pathways involving the typical Mnl(Ⅳ)-O· species or the recently proposed Mn4(Ⅶ)(O)2 species.Possible alternatives for the S2 → S3 and S3 → S4 transitions accounting for such required rearrangements are discussed.These findings reflect that the structural flexibility of the Mn4 Ca cluster is essential to allow structural rearrangements during the catalytic cycle.

• 单位
  西湖大学; 精细化工国家重点实验室