STRUCTURE AND FUNCTION OF CAROTENOIDS

本申请中包含的研究目的是 阐明类胡萝卜素的结构特征如何决定其 体内光化学性质。 类胡萝卜素是必需的 光合生物的生存。 本研究中要研究的系统 研究了几种不同光合细菌反应 中心和天线复合体已经被分离， 色素重构、色素交换、结晶或遗传 改变了 X射线晶体学和NMR分析将被用作直接的 结构探针 光学和EPR光谱学将允许 结构与光谱观测值和功能的相关性。 这些数据将为理解更复杂的 系统;例如，高等植物色素-蛋白质复合物，其性质 比细菌系统更复杂。 具体目标是 建议：（1）确定类胡萝卜素的结构， 光合色素-蛋白质复合物;（2）测定光合色素-蛋白质复合物的含量， 类胡萝卜素的结构与光谱的关系 （3）确定类胡萝卜素与植物生长的关系 类胡萝卜素转化细菌叶绿素的结构及其机理 单线态和细菌叶绿素-类胡萝卜素三线态能量转移。 我们已在2001年进行了几项初步研究， 支持我们提出的方法。

The objective of the research contained in this application is to elucidate how the structural features of carotenoids determine their photochemical properties in vivo. Carotenoids are essential for the survival of photosynthetic organisms. The systems to be studied in this investigation are several different photosynthetic bacterial reaction center and antenna complexes that have been isolated, pigment-reconstituted, pigment-exchanged, crystallized or genetically altered. X-ray crystallography and NMR analyses will be used as direct structural probes. Optical and EPR spectroscopy will allow the correlation of structure with spectroscopic observables and function. These data will provide a basis from which to understand more complex systems; e.g. higher plant pigment-protein complexes whose properties are more complex than the bacterial systems. The specific aims of this proposal are: (1) To determine the structures of carotenoids in photosynthetic pigment-protein complexes; (2) To determine the relationships between the carotenoid structures and their spectroscopic properties; (3) To determine the relationships between the carotenoid structures and their mechanisms of carotenoid-to-bacteriochlorophyll singlet and bacteriochlorophyll-to-carotenoid triplet energy transfer. Several preliminary studies have already been carried out by us in support of the methods which we propose to employ.