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Molecular Organization and Biodynamics of the Photosystem II Reaction Center

光系统II反应中心的分子组织和生物动力学

基本信息

批准号：
02454013
负责人：
SATOH Kimiyuki
金额：
$ 4.61万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1990
资助国家：
日本
起止时间：
1990 至 1991
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-02454013/
关键词：
Photosynthesis Photosystem II Reaction Center D1 protein Molecular Architecture Charge Separation Quinone Protein Synthesis 光化学系II反応中心 D1蛋白質 Pー680 EPR プロセシングプロテア-ゼ翻訳制御光化学反応中心 Cー末プロセシングクロロフィル

项目摘要

The efficient energy transformation in the primary process of photosynthesis is ensured by the highly ordered organization of photochemical reaction centers, in physical, chemical and biological sense. In photosystem II (PSII), the primary charge separation takes place in a pigmentprotein complex consisted of D1 and D2 proteins and some other components, which has recently been isolated and the chemical and physical properties have been analyzed (Nanba and Satoh, 1987). In the present study, the organization of PSII reaction center has been analyzed in two aspects. In the first part, stoichiometries of protein subunits and of pigments and redox cofactors of the isolated reaction center have been determined. The orientation of the primary donor (P-680) has been analyzed by EPR spectroscopy and it is deduced that the triplet state is localized on a chlorophyll, the tetrapyrrolic plane of which is tilted about 30ﾟ to the membrane. In the second part, the analysis has been focussed on some aspects of light-regulated turnover of D1 subunit of the PSII reaction center, which include the mechanism of light-regulated synthesis of D1 protein in isolated chloroplasts and the characterization of an enzyme involved in the C-terminal processing of D1 precursor protein. Determination of the levels of ATP in chloroplasts and the rate of synthesis of D1 protein under various conditions suggested that the level of ATP in soluble, stromal fraction controls the synthesis of D1 protein. The enzyme involved in the processing taking place after the synthesis has been extracted and purified.

光合作用初级过程中的有效能量转换是由光化学反应中心在物理、化学和生物学意义上的高度有序组织所保证的。在光系统II（PSII）中，初级电荷分离发生在由D1和D2蛋白以及一些其它组分组成的色素蛋白复合物中，最近已分离出该色素蛋白复合物并分析了其化学和物理性质（Nanba和Satoh，1987）。本研究从两个方面分析了PSII反应中心的结构。在第一部分中，化学计量的蛋白质亚基和色素和氧化还原辅因子的孤立的反应中心已被确定。用EPR谱分析了主给体（P-680）的取向，推测三重态位于叶绿素上，其四吡咯平面相对于膜倾斜约30 °。在第二部分中，我们着重分析了光系统Ⅱ反应中心D1亚基的光调控周转的一些方面，包括光调控叶绿体D1蛋白合成的机制和参与D1前体蛋白C-末端加工的酶的特性。在叶绿体中的ATP的水平和在各种条件下的D1蛋白的合成速率的测定表明，在可溶性，基质组分中的ATP的水平控制D1蛋白的合成。参与合成后发生的加工的酶已经被提取和纯化。