The family of Deg proteases in Arabidopsis thaliana

拟南芥中的 Deg 蛋白酶家族

• 批准号: 5447005
• 负责人: Professorin Dr. Iwona Adamska
• 金额: --
• 依托单位: Lehrstuhl für Physiologie und Biochemie der Pflanzen
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2005
• 资助国家: 德国
• 起止时间: 2004-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/5447005?language=en
• 关键词: family; Deg; proteases; Arabidopsis; thaliana

The Deg proteases are part of a large family of ATP-independent serine endopeptidases present in most organisms. In humans and Escherichia coli these proteolytic enzymes are implicated in the tolerance to various stresses, whereas very little is known about their functions in plants. homology searches in the A. thaliana database revealed the resence of 16 Deg homologues with a diverse subcellular location. Based on the evolutionary relationship these proteases cluster into four distinct groups, where group I has representatives in almost all organisms and group II (containing closely related Deg 2 and Deg9) is unique for higher plants. Group III and group IV are the most divergent and restricted to higher plants and fungi (Deg7) or higher plants and mammals (Deg15), respectively. Using in vitro assays we demonstrated that the chloroplast Deg2 protease degrades photodamaged D1 protein from the photosystem II reaction center under light stress conditions, thus catalyzing the key step in the repair cycle in plants. Here, we intend to continue our research on chloroplast Deg2 protease by: (a) solving a mechanism of the substrate recognition and specificity in vivo; (b) investigations of its dual location in the thylakoid membrane and stroma; (c) assaying the complex formation and interactions with other components and, (d) proving a possible chaperone activity and its role in photosystem II repair cycle. In addition, we would like to include three other proteases, Deg7, Deg9, Deg15, into our studies and to perform detailed localization and expression studies for these enzymes and to search for their physiological targets.

Deg蛋白酶是存在于大多数生物体中的ATP非依赖性丝氨酸内肽酶大家族的一部分。在人类和大肠杆菌中，这些蛋白水解酶与对各种胁迫的耐受性有关，而对它们在植物中的功能知之甚少。同源性搜索在A. thaliana数据库中发现16 Deg同源物存在于不同的亚细胞位置。基于进化关系，这些蛋白酶聚类为四个不同的组，其中组I在几乎所有生物中具有代表性，而组II（包含密切相关的Deg 2和Deg 9）在高等植物中是独特的。第三组和第四组是最分歧的，分别限于高等植物和真菌（Deg 7）或高等植物和哺乳动物（Deg 15）。利用体外试验，我们证明了叶绿体Deg 2蛋白酶降解光损伤的D1蛋白从光系统II反应中心在光胁迫条件下，从而催化在植物修复周期的关键步骤。在这里，我们打算继续我们对叶绿体Deg 2蛋白酶的研究：（a）解决在体内的底物识别和特异性的机制;（B）调查其在类囊体膜和基质中的双重位置;（c）分析复合物的形成和与其他组分的相互作用;（d）证明可能的伴侣活性及其在光系统II修复周期中的作用。此外，我们还希望将其他三种蛋白酶Deg 7，Deg 9，Deg 15纳入我们的研究中，并对这些酶进行详细的定位和表达研究，并寻找它们的生理靶点。