GENETIC ANALYSIS OF THE PHOTOSYNTHETIC REACTION CENTER

膜结合蛋白复合体参与许多重要的健康 相关的过程包括呼吸、运输过程、 转化、感觉转导、受体结合和信号 转导。细菌反应中心复合体，它介导一种 一系列有效的电子转移反应导致 将光转化为化学能，是唯一的膜蛋白 其结构已被确定为原子分辨率。而当 最高分辨率的结构数据(2.3埃)可从 绿色红假单胞菌表达系统的反应中心 这种生物体中的转基因反应中心不是 可用。我们一直在鉴定一种异养型RPS菌株。 绿色，这将被用来开发这样的遗传系统。RPS。 Viridis反应中心系统将提供测试机会 膜蛋白和蛋白质的底物识别/结合要求 生物系统中的电子转移理论，因为蛋白质 可以确定修饰的络合物的结构，然后进行关联 对这些相同的络合物进行生化和光谱研究。这个 RPS的PUF操纵子。Viridis(编码β和阿尔法亚单位 捕光复合体与L亚基、M亚基和细胞色素 反应中心子单元)将从RPS中删除。绿色 染色体。将使用包含PUF操纵子拷贝的质粒 来补充这一染色体缺失。色素-蛋白质结合 整个反应中心的相互作用将按地点进行修改- RPS的定向突变。绿色结构基因，其次是 蚀变岩的结晶学和光谱表征 反应中心复合体。RPS提供的见解。绿色 反应中心系统将为理解 其他膜蛋白中原子的结构-功能关系 分辨率结构信息不可用。

Membrane-bound protein complexes are involved in many important health related processes including respiration, transport processes, transformation, sensory transduction, receptor binding, and signal transduction. the bacterial reaction center complex, which mediates a series of efficient electron transfer reactions resulting in the conversion of light into chemical energy, is the only membrane protein whose structure has been determined to atomic resolution. While the highest resolution structural data (2.3 angstroms) is available from the reaction centers of Rhodopseudomonas viridis, a system for the expression of genetically modified reaction centers in this organism is not available. We have been characterizing a heterotrophic strain of Rps. viridis which will be used to develop such a genetic system. the Rps. viridis reaction center system will provide the opportunity to test substrate recognition/binding requirements in membrane proteins and theories of electron transfer in biological systems, since the protein structure of modified complexes can be determined and then correlated with biochemical and spectroscopic studies of these same complexes. The puf operon of Rps. viridis (encoding the beta and alpha subunits of the light harvesting complex and the L subunit, M subunit, and cytochrome subunit of the reaction center) will be deleted from the Rps. viridis chromosome. A plasmid containing a copy of the puf operon will be used to complement this chromosomal deletion. Pigment-protein binding interactions throughout the reaction center will be modified by site- directed mutagenesis of the Rps. viridis structural genes, followed by crystallographic and spectroscopic characterization of the altered reaction center complexes. The insights provided by the Rps. viridis reaction center system will provide a basis for understanding of structure-function relationships in other membrane proteins where atomic resolution structural information is not available.