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Molecular Organization of Photsystem II

Photsystem II 的分子组织

基本信息

批准号：
05304006
负责人：
SATOH Kimiyuki
金额：
$ 13.95万
依托单位：
Okayama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Co-operative Research (A)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1994
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-05304006/
关键词：
Photosynthesis Photosystem II Reaction Center Oxygen Evolution Crystallization Molecular Organization P-680 Mn-cluster 酸素発生系

项目摘要

I.Structural organization of photosystem IIThe photosystem II complexes of different integrities were isolated from thermophilic cyanobacteria. The structure and molecular interactions of the primary donor in the photosystem II reaction center have been investigated by detecting light-induced FT-IR difference spectra upon the formation of its triplet state. Considering the orientation of P-680 analyzed by EPR and the structure of bacteria reaction center determined by X-ray crystallography, together with the sequence homology between the D1 and D2 subunits of photosystem II and the L and M subunits of purple bacteria, a model of the structure of P-680 and its interactions with apoproteins has been proposed. Site-directed modification using Chlamydomonas reinhardtti of the amino acid side chains on D1 protein presumably involved in the hydrogen-bonding interaction (Ser-191 and Thr-192) has been succeeded and the analysis of these mutants is now in progress in order to prove this hypothesis. Chemical cross-linking analysis has also been conducted for the isolated photosystem II complexes to analyze the gross structure.II.Dynamic aspects of the organization of photosystem IIThe enzyme involved in the processing of D1 precursor protein has been identified and the partial amino acid sequences have been determined for spinach. Based on these data, a gene coding for the enzyme has been identified and sequenced. The recognition signal on substrate was analyzed for the C-terminal processing protease. Photo-tolerant mutants of an unicellular cyanobacterium Synechocystis PCC 6803 were obtained by in vitro random mutagenesis of psbAII (gene for D1 protein) by PCR under a condition for reduced fidelity of amplification, in order to analyze the damage-repair cycle of D1 protein ni photoinhibition of photosystem II reaction center.

从嗜热蓝藻中分离出不同完整性的光系统II复合物。通过光诱导FT-IR差谱研究了光系统II反应中心中主要给体的结构和分子间相互作用。结合EPR分析的P-680的取向和X射线晶体学测定的细菌反应中心结构，以及光系统II的D1和D2亚基与紫色细菌的L和M亚基的序列同源性，提出了P-680的结构及其与脱辅基蛋白相互作用的模型。利用莱茵衣原体对D1蛋白质上推测参与氢键相互作用的氨基酸侧链（Ser-191和Thr-192）进行的定点修饰已经成功，现在正在对这些突变体进行分析，以证明这一假设。化学交联分析也进行了分离的光系统II复合物，分析的总结构。II.动态方面的组织光系统IIThe酶参与的D1前体蛋白的加工已被确定和部分氨基酸序列已被确定为菠菜。基于这些数据，编码该酶的基因已被鉴定和测序。对底物上的识别信号进行分析，以确定C-末端加工蛋白酶。为了研究光系统II反应中心光抑制对D1蛋白损伤修复的影响，采用PCR技术，在降低扩增保真度的条件下，对单细胞蓝细菌集胞藻PCC 6803的psbA Ⅱ基因进行体外随机突变，获得耐光突变株。