STRUCTURE AND FUNCTION OF CAROTENOIDS

本申请中所包含的研究目的是 阐明类胡萝卜素的结构特征如何决定其 体内的光化学性质。类胡萝卜素对人体健康至关重要 光合作用有机体的生存。本研究拟研究的系统 研究了几种不同的光合细菌反应 已经被隔离的中心和天线复合体， 色素重组、色素交换、结晶或遗传 被更改了。X射线结晶学和核磁共振分析将作为直接使用 结构探头。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内容提供基础 系统；例如，高等植物色素-蛋白质复合体，其性质是 比细菌系统更复杂。这样做的具体目的是 建议：(1)确定红豆杉中类胡萝卜素的结构 光合色素-蛋白质复合体；(2)测定 类胡萝卜素结构与光谱的关系 性质；(3)确定类胡萝卜素与 类胡萝卜素转化为细菌叶绿素的结构及其机制 单线态和细菌叶绿素到类胡萝卜素三线态的能量转移。 我们已在#年进行了数项初步研究。 支持我们建议采用的方法。

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.