A new milestone for photosynthesis

• 来源期刊: 国家科学评论（英文版）
• 年，卷（期）: 2018,（4）
• 页码范围: 444-445
• 页数: 2页
• 语种: 英文
• DOI: 10.1093/nsr/nwx087

摘要

The photosynthetic water-splitting reaction catalysed by the oxygen-evolving center (OEC) in the photosystem Ⅱ of plants releases protons,electrons and dioxygen,which is one of the most important processes for energy and material conversions on Earth.OEC is a Mn4Ca-duster and cycles through five different states (Sn,n =0-4),wherein So is the most reduced state,S1 is the dark stable state and S2,S3 and S4 are intermediate states.OEC rapidly releases O2 in the S4 state,then returns to the So state.The detailed structure of the OEC in the S 1 state was reported by Umena et al.in 2011 [1]and improved by Suga et al.in 2015 [2].These reports from Shen's group have revealed that OEC is composed of an asymmetric Mn4CaO5-cluster coordinated by four water molecules,one imidazole and six carboxylate groups from protein side chains (Fig.1).Determination of the accurate structure of the OEC in the S1 state [1,2] is a breakthrough in the field of photosynthesis.However,because of the complexities of the large protein environment and the dynamic changes of the OEC during the water-splitting reaction,it is a great challenge to reveal its detailed reaction mechanism.