Electron Transfer in Cytochromes: Controlling Factors

这项工作的长期目标是描述这些因素 控制着生物系统中的电子转移 特别是在细胞色素C和B5中。 (1)蛋白质的作用 表面电荷将通过研究细胞色素进行评估， 改变静电表面。 (2)的速率常数 电子转移被认为是指数下降， 距离;这种距离依赖性又可以是一个函数 反应的驱动力。 狄克逊医生会 细胞色素B5系列。随着空间体积的增加， 电子转移位点 不同驱动下的速率常数 力将被测量。 由此产生的速率矩阵 常数将用于评估电子的依赖性 传递距离和驱动力。 (3)狄克逊医生会用 NMR技术测量电子转移速率常数 和蛋白质运动的一系列细胞色素c的影响， 了解分子基础的构象和 电子转移的重组控制。 特别 重点将放在细胞色素c的结构上， 离子强度的函数，对可逆 轴向蛋氨酸的损失和附近残基的作用 血红素控制电子转移。

The long term goal of this work is to delineate the factors which control electron transfer in biological systems specifically in cytochromes c and b5. (1) The role of protein surface charges will be evaluated by studying cytochromes with altered electrostatic surfaces. (2) The rate constant for electron transfer is thought to decrease exponentially with distance; this distance dependence may in turn be a function of the driving force for the reaction. Dr. Dixon will make a series of cytochromes b5. with increasing steric bulk at the electron transfer site. Rate constants at different driving forces will be measured. The resulting matrix of rate constants will be used to assess the dependence of electron transfer on distance and driving force. (3) Dr. Dixon will use NMR techniques to measure both electron transfer rate constants and protein motions for a series of cytochromes c in an effect to understand the molecular basis of conformational and reorganizational control of electron transfer. Particular emphasis will be placed on the structure of cytochrome c as a function of ionic strength, on the kinetics of the reversible loss of the axial methionine and on the roles of residues near the heme in controlling electron transfer.