The Role of Xanthophylls in the Mechanism of Nonradiative Energy Dissipation in Photosynthesis

叶黄素在光合作用非辐射能量耗散机制中的作用

• 批准号: 0314380
• 负责人: Harry Frank
• 金额: $ 41.99万
• 依托单位: University of Connecticut
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-01-01 至 2007-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0314380&HistoricalAwards=false
• 关键词: Role; Xanthophylls; Mechanism; Nonradiative; Energy

Photosynthetic organisms contain protective mechanisms by which excess light energy is dissipated before it leads to the photodestruction of the photosynthetic apparatus. Also, energy flow from light-harvesting pigment-protein complexes to the photosynthetic reaction center is highly regulated. The controlling features of these processes are not well understood. Xanthophyll pigments have been implicated in the mechanisms, but the precise nature of their involvement is unclear. In order to address this issue steady state absorption, fluorescence, two-photon excitation, and time-resolved absorption and fluorescence spectroscopic experiments will be performed. These experiments will probe the energies and electronic configurations of the excited states of the xanthophylls and measure the efficiencies and dynamics of energy transfer between the xanthophylls and chlorophylls. Also, electrochemical analyses will be done to examine the oxidation potentials of the molecules. The xanthophylls to be studied differ in their structures, extents of pi-electron conjugation, excited state energies and oxidation potentials. This research will investigate precisely how energy dissipation and energy flow regulation are accomplished through a systematic study of these molecules in native, recombinant, and reconstituted pigment-protein complexes isolated from higher plants and algae. The major objective of this study is to examine each of the molecular factors thought to be important in these processes in order to reveal the detailed mechanisms by which they take place in vivo. This work is expected to lead to a better understanding of how plants convert solar energy into chemical energy and withstand stress under excess solar energy conditions.The broader impacts of this study include having the participating students obtain experience in the techniques for the isolation, purification and characterization of biological materials and in sophisticated optical spectroscopic methodologies. Part of their training will include writing papers and making presentations at scientific meetings at which the results of the studies will be openly disseminated. This project also involves the participation of a faculty member from an undergraduate institution. His direct involvement in the project would expand his research horizons and will have an impact on the science education at a liberal arts undergraduate institution.

光合生物包含保护机制，在导致光合作用的光电隔离之前，通过这些机制散发出多余的光能。 同样，高度调节了从光收获色素 - 蛋白质复合物到光合反应中心的能量流。 这些过程的控制功能尚不清楚。 叶丁香颜料已经与机制有关，但其参与的确切性质尚不清楚。 为了解决这一问题，将进行稳态吸收，荧光，两光子激发以及时间分辨的吸收和荧光光谱实验。 这些实验将探测Xanthophylls激发态的能量和电子构型，并测量Xanthophylls和叶绿素之间能量转移的效率和动力学。 同样，将进行电化学分析以检查分子的氧化潜力。 要研究的黄藻植物在其结构，pi电子结合，激发状态能量和氧化电位方面有所不同。 这项研究将通过对这些分子的系统研究在天然，重组和重构的色素 - 蛋白质复合物中的系统研究来精确研究如何实现能量耗散和能量流量调节。 这项研究的主要目的是检查在这些过程中被认为很重要的每个分子因素，以揭示它们在体内发生的详细机制。 预计这项工作将使人们更好地了解植物如何将太阳能转化为化学能，并在太阳能条件下承受压力。这项研究的更广泛的影响包括让参与的学生获得有关生物材料和精致光学光谱方法的隔离，纯化和表征的技术的经验。 他们的一部分培训将包括写论文和在科学会议上进行演讲，在该会议上将公开传播研究结果。 该项目还涉及本科机构的教职员工的参与。 他对该项目的直接参与将扩大他的研究视野，并将对文科本科机构的科学教育产生影响。