Collaborative Research: Combining Theory and Experiment to Understand the First Photophysical Events in the Photoactivation of the Orange Carotenoid Protein

在化学系生命过程化学项目的支持下，康涅狄格大学(UConn)的JoséGascón教授和密歇根州立大学的Warren F.Beck教授将研究蓝藻用于保护自己免受过度暴露在阳光下的损害的机制。这个项目将确定与橙色类胡萝卜素(OCP)结合的酮类胡萝卜素如何作为光强度和颜色的传感器。主要目标是确定将OCP从静止的橙色形式(OCPO)转换为活动的红色形式(OCPR)的光物理机制；这种转换通过减缓光合作用能量存储的速度来保护有机体在高强度太阳照射下。这项工作将为蓝藻和绿色植物的光合作用装置中的组件如何共同工作，以分子形式存储太阳能，并避免光驱动的副反应造成损害提供洞察。这一新知识可能会对可用于太阳能应用的材料的设计和工程产生影响。这项研究将为研究生提供一个学习先进的计算机建模和光谱学技术及其在分子结构和功能高级研究中的应用的绝佳机会。此外，该项目将为参加美国国家科学基金会资助的本科生化学研究体验网站(REU)的高中生和本科生创造研究机会。计划中的研究结合了最先进的飞秒多维电子光谱和超灵敏的荧光方法，以感测OCPO中类酮类胡萝卜素在吸收蓝绿光时发生的构象变化。然后将使用电子结构计算和分子动力学模拟来建立类酮类胡萝卜素光激发后的第一个结构事件的分子模型。该研究计划将检验这一假设，即光驱动的类酮类胡萝卜素的构象变化启动了蛋白质的结构重组。这些研究预计将提供酮类胡萝卜素如何感知周围太阳照明的分子细节。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

With the support of the Chemistry of Life Processes Program in the Chemistry Division, Professor José Gascón from University of Connecticut (UConn) and Professor Warren F. Beck from Michigan State University will investigate the mechanisms that cyanobacteria employ to protect themselves from damage due to excessive exposure to sunlight. This project will determine how a ketocarotenoid bound to the orange carotenoid protein (OCP) serves as a sensor for the light intensity and color. The main goal is to determine the photophysical mechanism that converts the OCP from a resting, orange form (OCPO) to an active, red form (OCPR); this conversion protects the organism during high intensity solar illumination by slowing the rate of photosynthetic energy storage. The work will provide insight in how the components in the photosynthetic apparatus of cyanobacteria and green plants work together to store solar energy in molecular form and to avoid light-driven side reactions that cause damage. The new knowledge could impact the design and engineering of materials that can be used in solar energy applications. The research will afford an excellent opportunity for graduate students involved to learn advanced computer modeling and spectroscopy techniques and their application to advanced studies of molecular structure and function. In addition, the project will create research opportunities for high school students from the School of Exploratory Chemical Research and Training (SECRET) and undergraduate students who participate in the NSF-funded Research Experiences for Undergraduates (REU) site in Chemistry at UConn.The planned research involves a combination of state-of-the-art femtosecond multidimensional electronic spectroscopy and ultrasensitive fluorescence methods to sense the conformational changes that the ketocarotenoid undergoes in OCPO when it absorbs blue-green light. Electronic structure calculations and molecular dynamics simulations will then be used to develop a molecular model for the first structural events that follow photoexcitation of the ketocarotenoid. The research plan will test the hypothesis that light-driven conformational changes of the ketocarotenoid initiate the structural reorganization of the protein. These studies are expected to provide molecular details of how the ketocarotenoid senses ambient solar illumination.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.