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Anovel degradation pathway of the D1 protein under light stress

光胁迫下D1蛋白的新降解途径

基本信息

批准号：
13640650
负责人：
YAMAMOTO Yasusi
金额：
$ 0.38万
依托单位：
OKAYAMA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13640650/
关键词：
Photosvstem II Photoinhibition Reactive oxygen species Protease Protein aggregation Oxygen evolution Reaction center D1 protein 光合成 D1タンパク質品質管理タンパク質架橋

项目摘要

Under light stress conditions, the reaction center binding D1 protein of photosystem II is degraded rapidly. In the present study, we found a novel pathway of D1 degradation. We characterized the pathway in detail and also studied the components involved in the pathway. The main results obtained are as follows :1. Isolation of a protease(s) degrading the cross-linked products of the D1 protein from the stioma : During the photoinhibition of photosystem II, the D1 protein cross-links with the surrounding polypeptides. We partiafly purified a protease(s) that recognizes and digests the cross-linked products from the fraction of stroma, using a gelatin activity gel.2. Determination of spatial arrangement of the D1 protein and neighboring polypeptides in photosystem II with the use of phofco-crossnnking reaction : We determined the relative arrangement of the D1 protein, CP43 andOEC33.in the lumenal side of photosystem II. These proteins are essential for the oxygen evolving activity of photosystem II, and the information obtained here is crucial for the structural analysis of the oxygen evolving system.3. Induction of singlet oxygen under heat and light stresses in photosystem II and the generation of cross-linked products of the D1 protein with the neighboring polypeptides : We found that formation of singlet oxygen by the illumination of PS II is stimulated under heat stress. The singlet oxygen was the main cause for the protein cross-linking in photosystem II.

在光胁迫条件下，光系统II的反应中心结合D1蛋白迅速降解。在本研究中，我们发现了 D1 降解的新途径。我们详细描述了该途径，并研究了该途径中涉及的成分。取得的主要结果如下： 1．从孔口中分离降解 D1 蛋白交联产物的蛋白酶：在光系统 II 的光抑制过程中，D1 蛋白与周围的多肽交联。我们使用明胶活性凝胶部分纯化了一种蛋白酶，该蛋白酶可以识别并消化基质部分中的交联产物。2．利用光交联反应确定光系统 II 中 D1 蛋白和邻近多肽的空间排列：我们确定了 D1 蛋白、CP43 和 OEC33 在光系统 II 腔侧的相对排列。这些蛋白质对于光系统II的放氧活性至关重要，这里获得的信息对于放氧系统的结构分析至关重要。3．光系统 II 中热和光应激下单线态氧的诱导以及 D1 蛋白与邻近多肽交联产物的生成：我们发现，在热应激下，PS II 的照射刺激了单线态氧的形成。单线态氧是光系统II中蛋白质交联的主要原因。