Ultrafast Studies of Electron Transfer in Photosystem II

光系统 II 中电子转移的超快研究

• 批准号: 9727948
• 负责人: Roseanne Sension
• 金额: $ 25.5万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-03-01 至 2002-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9727948&HistoricalAwards=false
• 关键词: Ultrafast; Studies; Electron; Transfer; Photosystem

9727948 Sension In this research project state-of-the-art ultrafast spectroscopic techniques will be used to study the primary electron transfer processes in photosystem II. Three specific lines of attack will be pursued in this series of investigations. (1) Ultrafast fluorescence detection will be used to study the excited state population dynamics directly in the D1-D2-Cyt b559 reaction center complex. A streak camera of novel design, which provides greater flexibility, superior signal averaging and sub five picosecond time resolution, will be used. These characteristics are necessary for the study of energy transfer and change separation in PSII. (2) Larger PSII complexes will be prepared in order to study the electron transfer rate in active centers and set to rest any speculation as to whether or not the D1-D2-Cyt b559 complex retains the native reaction center structure and dynamics. The studies will investigate the D1-D2-Cyt b559 complex, the CP47-D1-D2-Cyt b559 complex, and the reaction center core under consistent conditions permitting direct and quantitative comparisons. (3) Finally, the addition of external replacement quinones will be used to study the primary and secondary electron transfer processes in PSII. These measurements will be performed on the D1-D2-Cyt b559 complex and the CP47-D1-D2-Cyt b559 complex. These studies will explore the effect of the presence of a secondary electron acceptor on the population equilibrium distributed over the locally excited fluorescent and charge separated dark states. A rigorous understanding of the primary electron transfer reactions in biological photosynthetic systems is one of the keys to a complete understanding of natural solar energy conversion. The protein complex referred to as photosystem II is responsible for the ability of green plants to utilize light energy to fuel the production of oxygen from water. The PSII protein complex works in conjunction with a second complex, photosystem 1, to form carbohydrates from carbon dioxide. From a chemical point of view, the ability of green plants to produce oxygen and carbohydrates from light, water and carbon dioxide represents an amazing achievement. The overall goal of this investigation is to understand the factors that control the efficiency of photosynthesis in green plants.

9727948在这项研究项目中，最先进的超快光谱技术将用于研究Photosystem II中的主要电子传输过程。 在这一系列调查中将采用三种特定的攻击线。 （1）超快荧光检测将直接在D1-D2-CYT B559反应中心复合体中直接研究激发态种群动力学。 新型设计的条纹摄像头将使用更大的灵活性，较高的信号平均和五次皮秒时间分辨率。 这些特征对于PSII中的能量转移和变化分离是必需的。 （2）将准备较大的PSII复合物，以研究活跃中心的电子传递速率，并设置出关于D1-D2-CYT B559复合物是否保留天然反应中心结构和动力学的任何猜测。 研究将研究D1-D2-CYT B559复合物，CP47-D1-D2-CYT B559复合物，以及在允许直接和定量比较的一致条件下的反应中心核心。 （3）最后，将添加外部替换奎因酮将用于研究PSII中的主要和次级电子传递过程。 这些测量将在D1-D2-CYT B559复合物和CP47-D1-D2-CYT B559复合物上进行。 这些研究将探索二级电子受体的存在对分布在局部激发荧光和电荷分离的暗状态的种群平衡的影响。 对生物光合系统中的主要电子转移反应的严格理解是完全理解自然太阳能转化率的关键之一。 被称为光系统II的蛋白质复合物负责绿色植物利用轻能来为水从水中产生氧气的能力。 PSII蛋白质复合物与第二个复合物光学系统1结合起作用，以形成二氧化碳的碳水化合物。 从化学的角度来看，绿色植物从光，水和二氧化碳产生氧气和碳水化合物的能力代表了一个惊人的成就。 这项研究的总体目标是了解控制绿色植物光合作用效率的因素。