Structure and Function of Carotenoids

类胡萝卜素的结构和功能

• 批准号: 1243565
• 负责人: Harry Frank
• 金额: $ 56.79万
• 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: 2013
• 资助国家: 美国
• 起止时间: 2013-03-01 至 2017-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1243565&HistoricalAwards=false
• 关键词: Structure; Function; Carotenoids

Carotenoids are naturally-occurring pigments that are essential for the survival of photosynthetic organisms. They act as protective devices against irreversible photodestruction of the photosynthetic apparatus, and they function as light-harvesting pigments. Despite this general knowledge of carotenoid behavior obtained from years of investigations, the excited state spectra and dynamics of these molecules are still not well understood. Many of the assignments of their energy states from spectroscopic data are controversial, and the precise nature of the excited states and the roles they play in controlling the biological functions of carotenoids remain unclear. The overall objective of the project is to elucidate the excited state spectra and dynamics of carotenoids in order to reveal how they carry out their important roles in nature. The planned experiments will analyze systematic series of polyenes and carotenoids obtained either synthetically or from several different photosynthetic organisms. In addition, recombinant proteins refolded with modified chlorophylls, or having undergone site-directed mutagenesis in the vicinity of protein-bound pigments, will be studied. Ultrafast time-resolved spectroscopic methods will be used to measure the spectra and dynamics of the excited states. The experiments will be augmented by theoretical quantum mechanical computations to reveal the excited state configurations which will be correlated with the spectroscopic observables. Kinetic and quantum mechanical models describing the photochemical behavior of carotenoids will be evaluated. Various hypotheses pertaining to the excited state structure and spectral properties of carotenoids will be tested, and a number of issues regarding how carotenoids function will be addressed.Broader impactsThe subject of the research has broad relevance to several socially important topics including global climate change, biofuels, and the development of alternative solar energy conversion schemes. A critical aspect of this project will be its impact on the training of undergraduate and graduate students which include those from underrepresented groups recruited though several outreach activities in which the PI will continue to participate. In the laboratory of the PI, the students will gain experience in a broad spectrum of experimental approaches including the techniques for the isolation and characterization of complex biological materials, sophisticated molecular spectroscopic methodologies, and kinetic and quantum computational modeling. The students will develop organizational and problemsolving skills by writing reports and publications and making presentations at scientific meetings to obtain valuable critical feedback from experts in the field. In addition, the PI will advance general understanding of the project by incorporating the subject matter directly into the freshman-level General Chemistry and graduate Biological and Physical Chemistry courses and through outreach activities involving the general public. The PI will be giving presentations at various schools where he will speak not only about the scientific content, but also about the broad social impacts of the project. The PI will continue his active role as a mentor in the NSF-sponsored REU program in the Department of Chemistry where a participating student will work directly on the project. Finally, the PI has established collaborative arrangements with internationally-known experts who will interact freely with the students in the group specifically on work related to this project, offer a global perspective on the work, and help bring the studies to fruition as rapidly as possible.This project is jointly supported by the Molecular Biophysics program in the Division of Molecular and Cellular Biosciences and the Chemical Structure, Dynamics and Mechanism and Chemistry of Life Processes programs in the Chemistry Division

类胡萝卜素是天然存在的色素，对光合生物的生存至关重要。它们作为一种保护装置，防止光合作用装置受到不可逆的光破坏，它们的功能是光收集色素。尽管从多年的研究中获得了类胡萝卜素行为的一般知识，但这些分子的激发态光谱和动力学仍然没有得到很好的理解。从光谱数据中对它们的能量状态的分配是有争议的，激发态的确切性质以及它们在控制类胡萝卜素的生物功能中所起的作用仍然不清楚。该项目的总体目标是阐明类胡萝卜素的激发态光谱和动力学，以揭示它们如何在自然界中发挥重要作用。计划中的实验将分析系统的多烯和类胡萝卜素系列，这些多烯和类胡萝卜素要么是合成的，要么是从几种不同的光合作用生物中获得的。此外，还将研究用修饰的叶绿素重新折叠的重组蛋白，或在蛋白质结合色素附近进行定点诱变的重组蛋白。超快时间分辨光谱方法将用于测量激发态的光谱和动力学。实验将通过理论量子力学计算来增强，以揭示与光谱观测相关的激发态构型。描述类胡萝卜素光化学行为的动力学和量子力学模型将被评估。关于类胡萝卜素的激发态结构和光谱特性的各种假设将被测试，以及一些关于类胡萝卜素功能的问题将被解决。更广泛的影响这项研究的主题与几个重要的社会话题有广泛的相关性，包括全球气候变化、生物燃料和替代太阳能转换计划的发展。这个项目的一个关键方面将是它对培训本科生和研究生的影响，其中包括那些来自代表性不足群体的学生，这些学生是通过PI将继续参加的几项外联活动征聘的。在PI的实验室里，学生将获得广泛的实验方法的经验，包括分离和表征复杂生物材料的技术，复杂的分子光谱方法，以及动力学和量子计算建模。学生将通过撰写报告和出版物以及在科学会议上发表演讲来培养组织和解决问题的能力，以获得该领域专家的宝贵批评反馈。此外，PI将通过将主题直接纳入大一学生的普通化学和研究生的生物和物理化学课程，以及通过涉及公众的外展活动，促进对该项目的普遍理解。PI将在不同的学校做演讲，他不仅会讲科学内容，还会讲项目的广泛社会影响。PI将继续在美国国家科学基金会资助的化学系REU项目中担任导师，参与该项目的学生将直接参与该项目。最后，PI与国际知名专家建立了合作安排，他们将与小组中的学生自由互动，特别是与该项目相关的工作，提供工作的全球视角，并帮助尽快实现研究成果。本项目由分子与细胞生物科学部的分子生物物理学项目和化学部门的化学结构、动力学与机制和生命过程化学项目共同支持