Characterization of Reaction Centers with Altered Donor Oxidation Potentials

9404925艾伦这个项目的目标是了解生物系统可以将光能转化为化学能的过程，其效率接近1。 光合生物最初的光化学过程发生在一个称为反应中心的色素-蛋白质复合体中。 光化学过程由光吸收引发，光吸收激发细菌叶绿素二聚体并开始电子和质子的转移，电子和质子将用于产生富含能量的化合物。 这些电子转移过程的一个关键特征是速率和驱动力之间的关系。 我们建议测量后，我们已经显着改变了驱动力的细菌叶绿素二聚体的能量水平的具体变化的过程。 我们计划使用范围广泛的技术，从飞秒瞬态吸收光谱和电子核顺磁共振光谱的分子生物学。 对这种复合物中的电子传递过程的理解对于其他生物系统，如呼吸和电子传递链以及氧化还原酶应该是有用的。 这项研究的目标是在分子水平上了解生物系统的功能。 所有生物过程的基础是使用能量来产生富含能量的化合物。 这些研究旨在了解生物有机体如何有效地将光转化为化学能。 我们的方法是研究被称为反应中心的复合物，它参与了这个转化过程的初始步骤。 我们通过分子生物学改变复合物，然后应用物理技术来表征功能如何改变。 更具体地说，我们做出改变，改变反应的驱动力，然后测量反应速率的变化。 虽然这项研究适用于一个特定的复杂，我们预计，结果将是普遍的，适用于其他生物系统。 ***

9404925 Allen The goal of this project is to understand the process by which biological systems can convert light energy into chemical energy with an efficiency near unity. The initial photochemical process in photosynthetic organisms occurs in a pigment-protein complex called the reaction center. The photochemical process is initiated by light absorption that excites a bacteriochlorophyll dimer and starts the transfer of electrons and protons that will be used to generate energy rich compounds. A critical feature of these electron transfer processes is the relationship between the rate and driving force. We propose measuring the process after we have significantly altered the driving force by making specific changes in the energy levels of the bacteriochlorophyll dimer. We plan to use a wide range of techniques ranging from femotosecond transient absorption spectroscopy and electron nuclear paramagnetic resonance spectroscopy to molecular biology. The understanding of the electron transfer processes in this complex should be useful for other biological systems, such as respiratory and electron transfer chains and redox enzymes. %%% The goal of this research is to understand the function of biological systems at a molecular level. Fundamental to all biological processes is the use of energy to create energy rich compounds. These research seeks to understand how biological organisms efficiently convert light into chemical energy. Our approach is to study the complex called the reaction center, that is involved in the initial steps of this conversion process. We alter the complex by use of molecular biology and then apply physical techniques to characterize how the function has changed. More specifically, we make changes that alter the driving force for the reaction and then measure how the rate of the reaction changes. Although the study is applied to a specific complex, we anticipate that the results will be general and applicable to other biological systems. ***