Structural Insights into Substrate Selectivity, Catalytic Mechanism,and Redox Regulation of Rice Photosystem Ⅱ Core Phosphatase  

作　　者：Xiuying Liu Jingchao Chai Xiaomin Ou Mei Li Zhenfeng Liu 

机构地区：[1]National Laboratory of Biomacromolecules,CAS Center for Excellence in Biomacromolecules,Institute of Biophysics,Chinese Academy of Sciences, Beijing 100101,P.R.China [2]University of Chinese Academy of Sciences,Beijing 100049,P.R.China

出　　处：《Molecular Plant》2019年第1期86-98,共13页分子植物（英文版）

基　　金：the National Key R&D Program of China (2017YFA0503702);the Strategic Priority Research Program of CAS (XDB08020302);the Key Research Program of Frontier Sciences of CAS (QYZDB-SSW-SMC005);the National Natural Science Foundation of China (31670749).

摘　　要：Photosystem Ⅱ (PSII)core phosphatase (PBCP)selectively dephosphorylates PSII core proteins including D1,D2,CP43,and PsbH.PBCP function is required for efficient degradation of the D1 protein in the repair cycle of PSII,a supramolecular machinery highly susceptible to photodamage during oxygenic photosynthesis.Here we present structural and functional studies of PBCP from Oryza sativa (OsPBCP).In a symmetrical homodimer of OsPBCP,each monomer contains a PP2C-type phosphatase core domain,a large motif characteristic of PBCPs,and two Small motifs around the active site.The large motif contributes to the formation of a substrate-binding surface groove,and is crucial for the selectivity of PBCP toward PSII core proteins and against the light-harvesting proteins.Remarkably,the phosphatase activity of OsPBCP is strongly inhibited by glutathione and H202.S-Glutathionylation of cysteine residues may introduce steric hindrance and allosteric effects to the active site.Collectively,these results provide detailed mechanistic insights into the substrate selectivity,redox regulation,and catalytic mechanism of PBCP.

关 键 词：PSII CORE PHOSPHATASE structure substrate SELECTIVITY redox regulation PSII REPAIR cycle 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]