Collaborative Research: Unraveling the Initial Charge Separation Mechanism in Photosystem I: A Synergistic Approach

在化学系生命过程化学项目的支持下，路易斯安那大学拉斐特分校的吴旭教授和普渡大学的Sergei Savikhin教授和Lyudmila Slipchenko教授将研究光系统I复合物中初始电荷转移的分子机制。光系统I存在于地球上所有的植物、藻类和产氧细菌中。它是光合作用机制的主要组成部分之一，捕获阳光的能量并为地球上的生命提供动力。拟议研究的目标是提供一个详细而明确的过程，使光系统I能够将吸收的阳光转化为电荷的运动，即电流。这项工作将通过遗传工程，超快光谱学和预测分子建模的独特协同组合进行。拟议研究的实际价值在于其对自然和生物启发的能源生产系统的进步的潜在影响。这项工作将为研究生和本科生提供真正的多学科经验，并加强这种合作在未来一代科学家中的作用。关于光系统I反应中心初级电荷分离的动力学和分子机理还没有达成共识。拟议的工作将解决这些研究问题。针对光系统I反应中心内各种辅助因子的性质的基因工程结合超快光学光谱将提供丰富的数据，这些数据携带复合物中电子转移的间接信息。这些数据将用于验证和完善第一原理建模策略，其中唯一的实验输入是光系统I复合物的结构。经验证的第一性原理模型将有助于解释实验数据，并提出新的特定突变与预期的影响光系统I的属性。这个多方面的、协同的项目由一个在光合作用研究方面具有广泛专业知识和经验的研究人员团队进行，并建立了合作记录。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值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 Division of Chemistry, Professor Wu Xu from the University of Louisiana at Lafayette, and Professors Sergei Savikhin and Lyudmila Slipchenko from Purdue University will investigate the molecular mechanism of the initial charge transfer in photosystem I complex. Photosystem I is found in all plants, algae, and oxygenic bacteria on Earth. It is one of the major components of photosynthetic machinery that captures the energy of sunlight and powers life on the planet. The goal of the proposed research is to provide a detailed and unambiguous picture of the process that enables photosystem I to convert absorbed sunlight into motion of charges, i.e. electrical current. The work will be conducted through the unique synergistic combination of genetic engineering, ultrafast optical spectroscopy, and predictive molecular modeling. A practical value of the proposed research is in its potential impact on the advancement of natural and bio-inspired systems for energy production. This work will provide graduate and undergraduate students with truly multidisciplinary experience and reinforce the role of such collaborations in the future generation of scientists.Despite three decades of intense investigation, critical details of charge separation in photosystem I are still lacking. There is no consensus on the kinetics and molecular mechanism of the primary charge separation in the photosystem I reaction center. The proposed work will address these research questions. Genetic engineering targeting the properties of various cofactors within the photosystem I reaction center combined with ultrafast optical spectroscopy will provide a wealth of data that carries indirect information on the electron transfer in the complex. This data will be used to validate and refine first-principles modeling strategies in which the only experimental input is the structure of the photosystem I complex. The validated first-principles model will facilitate the interpretation of the experimental data and suggest new specific mutations with anticipated effects on photosystem I properties. This multifaceted, synergistic project is being conducted by a team of investigators who have extensive expertise and experience in photosynthetic research and an established track record of collaboration.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.