Spin Coherences in Photosystem I Reaction Center Proteins and Model Systems

光系统 I 反应中心蛋白质和模型系统中的自旋相干性

• 批准号: 1112258
• 负责人: Michael Wasielewski
• 金额: $ 36万
• 依托单位: Northwestern University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-07-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1112258&HistoricalAwards=false
• 关键词: Spin; Coherences; Photosystem; Reaction; Center

This award in the Chemistry of Life Processes (CLP) program supports work by Professor Michael R. Wasielewski at Northwestern University to carry out fundamental studies on the nature of multiple pathways for light-induced charge separation in one of the key light transduction proteins in green plants, the Photosystem I (PSI) reaction center (RC), which is responsible for providing the chemical potential necessary to reduce carbon dioxide to carbohydrates. The PSI RC in oxygenic organisms is unique because it is the only RC for which there is evidence that both sets of redundant cofactors engage in electron transport. The electron transfer cofactors in the PSI RC protein are arranged in two symmetric pathways, A and B, which results in charge transport to a common electron acceptor, and suggests the possibility that the PSI protein may function as an interferometer in which electrons traversing the two pathways are in a quantum superposition state. This project will address two key questions regarding the role of quantum superposition in PSI function: 1) Does charge transport within PSI involve independent spin-coherent radical ion pairs using either the A and B pathways or a quantum superposition state involving both pathways simultaneously? 2) Does the inherent quantum coherent nature of the dual-pathway charge separation sense and control excess excitation energy dissipation in the PSI RC? Time-resolved electron paramagnetic resonance spectroscopy will be used to probe these mechanisms, while theory and synthetic donor-acceptor systems will be used to model this behavior.Understanding excess energy dissipation in photosynthetic organisms is critical to ensuring the viability and sustainability of photosynthetic energy transduction in nature, a process essential to life on Earth. Improved knowledge of this process provides an important conceptual basis for the design of artificial photosynthetic systems for solar energy conversion. The results of this research will be communicated to the public through the extensive outreach network of the Northwestern-funded Initiative for Sustainability and Energy at Northwestern (ISEN).

生命过程化学（CLP）计划中的这一奖项支持了Michael R. Wasielewski在西北大学进行基础研究的光诱导电荷分离的多个途径的性质在绿色植物的关键光转导蛋白之一，光系统I（PSI）反应中心（RC），这是负责提供必要的化学势，以减少二氧化碳的碳水化合物。 PSI RC在产氧生物体是独特的，因为它是唯一的RC，有证据表明，这两套冗余的辅因子从事电子传递。 PSI RC蛋白中的电子转移辅因子被安排在两个对称的路径，A和B，这导致电荷传输到一个共同的电子受体，并建议PSI蛋白可能作为一个干涉仪的功能，其中穿过两个路径的电子处于量子叠加态的可能性。 这个项目将解决两个关键问题，量子叠加在PSI功能的作用：1）PSI内的电荷传输是否涉及独立的自旋相干自由基离子对使用任何一个A和B路径或量子叠加态涉及两个途径同时？ 2)双通道电荷分离的固有量子相干性质是否感测和控制PSI RC中的过量激发能量耗散？ 时间分辨电子顺磁共振光谱将被用来探测这些机制，而理论和合成供体受体系统将被用来模拟这种behavior.Understanding过剩的能量耗散在光合生物是至关重要的，以确保光合能量转导的可行性和可持续性在自然界中，地球上的生命必不可少的过程。 对这一过程的进一步了解为设计用于太阳能转换的人工光合系统提供了重要的概念基础。 这项研究的结果将通过西北资助的西北可持续发展和能源倡议（伊森）的广泛外联网络向公众传达。