The Role of the D2 Protein in the Photosystem II Complex as Probed by Directed Mutagenesis and Mutant Analysis

通过定向诱变和突变分析探讨 D2 蛋白在光系统 II 复合体中的作用

基本信息

批准号：
8716055
负责人：
Willem Vermaas
金额：
$ 20.76万
依托单位：
Arizona State University
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1988
资助国家：
美国
起止时间：
1988-01-15 至 1991-06-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=8716055&HistoricalAwards=false
关键词：
Role D2 Protein Photosystem II

项目摘要

The D2 protein is a central component of the Photosystem II complex in photosynthetic membranes, but its precise function is unknown. The role of specific amino acid residues and polypeptide regions of D2 in function, structure and assembly of the Photosystem II complex is being studied by directed mutagenesis techniques. Specific mutations are induced D2. The psbD-I gene (encoding D2) carrying site-directed mutations is introduced into a mutant of the transformable photoheterotrophic cyanobacterium Synechocystis 6803, from which the two psbD gene copies (psbD-I and psbD-II) have been deleted. Target regions to create D2 mutations are identified in part by comparison with the partially homologous M subunit of the reaction center from purple bacteria, for which the detailed structure is known. The properties of the mutant Photosystem II complex are analyzed in a variety of ways, including mRNA studies, and analysis of Photosystem II protein composition and synthesis, electron transport, chlorophyll fluorescence, specific EPR signals, herbicide binding, and flash-induced absorbance changes. The results of this project will lead to a detailed understanding of the role of specific residues and regions in an important but poorly understood protein in photosynthetic membranes. Insight will be gained on how the oxidizing complex is organized. Potentially significant is that the protein complex can be altered to result in more efficient operation.***//

D2蛋白是光合膜中光系统II复合物的核心组成部分，但其精确功能尚不清楚。通过定向诱变技术研究了D2的特定氨基酸残基和D2的多肽区域在光系统II配合物的功能，结构和组装中的作用。特异性突变是诱导的D2。携带位点定向突变的PSBD-I基因（编码D2）被引入可转化的光旋转藻类菌杆菌共形成藻6803的突变体中，从中两个PSBD基因拷贝（PSBD-I和PSBD-II）已被删除。与紫色细菌的反应中心的部分同源的M亚基相比，可以部分鉴定出创建D2突变的目标区域，紫色细菌已知详细的结构。通过多种方式分析了突变体光系统II复合物的性能，包括mRNA研究，分析光系统II蛋白质组成和合成，电子传输，叶绿素荧光，特定的EPR信号，除草剂结合以及闪光灯诱导的吸收性变化。该项目的结果将导致对特定残基和区域在光合膜中蛋白质中特定残基和区域的作用的详细了解。将在如何组织氧化复合物中获得洞察力。潜在的意义是可以改变蛋白质复合物以实现更有效的运行。*** //