Metalloprotein Electron Transfer Mechanisms

在这个由无机化学、生物无机化学和金属有机化学计划支持的项目中，加州理工学院的哈里·B·格雷将研究控制生物系统中远程电子转移的因素。这些研究将有助于更好地理解生命过程中的生化氧化还原机制。将研究抹香鲸肌红蛋白和马心脏细胞色素c的几种衍生物的电子转移速率与供体-受体分离和反应驱动力(吉布斯自由能)的关系。将开发一种方法来用毒胺-Ru-吡啶络合物修饰表面组氨酸，这将允许引入有机受体部分在肌红蛋白表面的四个明确位置。半合成程序将被用来将有机受体放置在细胞色素c内的-82位(苯丙氨酸-82将被氟和氰基苯丙氨酸取代)。对修饰后的肌红蛋白进行联合驱动力/变距离电子转移实验。我们将研究锌卟啉/82位受体细胞色素c衍生物中的光致电荷分离和电荷复合反应。

In this project supported by the Inorganic, Bioinorganic and Organometallic Chemistry Program, Harry B. Gray of the California Institute of Technology will investigate the factors that control long-range electron transfer in biological systems. The studies will lead to a better understanding of the biochemical oxidation-reduction mechanisms in life processes. The dependence of the rate of electron transfer on donor- acceptor separation and reaction driving force (Gibbs free energy) will be studied in several derivatives of sperm whale myoglobin and horse heart cytochrome c. A methodology will be developed to modify surface histidines with tetraammine- ruthenium pyridinium complexes which will allow introduction of organic acceptor moieties in four well-defined positions on the surface of myoglobin. Semisynthetic procedures will be used to place organic acceptors at position-82 inside cytochrome c (phenylalanine-82 will be replaced by fluoro- and cyano-phenyl- alanines). Combined driving force/distance-variation electron transfer experiments will be carried out on the modified myoglobins. Photoinduced charge separation and charge recombination reactions in zinc porphyrin/position-82-acceptor cytochrome c derivatives will be investigated.