Synthetic Model of the Oxygen‐Evolving Center: Photosystem II under the Spotlight

Abstract

The oxygen-evolving center (OEC) in photosystem II catalyzes a water splitting reaction. Great efforts have already been made to artificially synthesize the OEC, in order to elucidate the structure-function relationship and the mechanism of the reaction. Now, a new synthetic model makes the best mimic yet of the OEC. This recent study opens up the possibility to study the mechanism of photosystem II and photosynthesis in general for applications in renewable energy and synthetic biology.

Mimicking the Catalytic Center for the Water-Splitting Reaction in Photosystem II

“…Artificial Mn 4 CaO 4 -clusters shown in Figures 9 and 13 have mimicked the main structural motifs of the OEC, which could provide distinct chemical insight into understanding the principle of the OEC [127,131,132]. First, the successful isolation of different artificial Mn 4 CaO 4 -complexes demonstrates that the Mn 4 CaO 4 -cluster is thermodynamically stable, which supports the proposal that the Mn 4 CaO 4 -cluster could be an evolutionary origin of the natural OEC by Barber [133].…”

Structural models of the biological oxygen-evolving complex: achievements, insights, and challenges for biomimicry

“…Such characteristic signals had never been observed before in other synthetic structural models of the OEC. 219 Zhang et al could detect subtle structural differences, particularly in the Mn1-Mn4 and Ca-O4 distances between two monomers in the crystallographic unit cell of the neutral state. They assumed that the structural difference, possibly amplified during solvation or S 1 to S 2 state change, could affect the exchange coupling between Mn ions leading to two different spin states, which might explain the simultaneous appearance of two signals.…”

From natural photosynthesis to artificial photosynthesis

“…上述研究显示, 人工Mn4Ca-簇合物不仅在结构上 与OEC类似, 而且在理化性能上也与OEC类似. 这类 人工Mn4Ca-簇合物的获得为研究OEC的结构和催化 机理提供了理想的化学模型, 同时对今后制备廉价、 高效人工水裂解催化剂有重要的科学意义和应用价 值 [82,83] .…”