Electron Transfer Reactions Between Cytochrome c, Cytochrome c Oxidase and Dioxygen

这项研究由化学部的分析和表面化学项目支持，将研究细胞色素c氧化酶的电子传递热力学、动力学和酶作用机制。酶将被吸附到金电极上并嵌入到脂质双分子层中。通过电化学和光谱测量（包括磁圆二色性），将研究氧化/还原过程的电动力学和结构动力学。脂质双分子层的使用将防止酶亚基在电极表面聚集，从而提高了观察到的动力学对应于所需的特定单位而不是聚集的可能性。细胞色素c是一种普遍存在的生物转移剂。呼吸和光合作用的效率很大程度上取决于细胞色素c与两种酶（细胞色素c氧化酶和细胞色素c还原酶）之间的电子转移动力学。本研究将通过在金电极上吸附细胞色素c还原酶来研究电子传递动力学，否则将被脂质双分子层覆盖以模拟细胞膜。这项工作的目标是观察由于电子转移导致的酶的构象变化；这种变化被假设为有效的生物电子转移过程的基本特征。

This research, supported by the Analytical and Surface Chemistry Program in the Chemistry Division, will study electron transfer thermodynamics, kinetics, and mechanisms of enzyme action for cytochrome c oxidase. The enzyme will be adsorbed to a gold electrode and embedded in a lipid bilayer. Through both electrochemical and spectroscopic measurements (including magnetic circular dichroism) the electrical and structural dynamics of oxidation/reduction processes will be studied. The use of lipid bilayers will keep enzyme subunits from clustering at the electrode surface, improving the likelihood that the dynamics observed correspond to the specific units desired rather than to agglomorates. %%% Cytochrome c is a ubiquitous biological transfer agent. The efficiency of respiration and photosynthesis are largely dependent on the dynamics of electron transfer between cytochrome c and two enzymes: cytochrome c oxidase and cytochrome c reductase. This research will study the electron transfer dynamics by adsorbing cytochrome c reductase on a gold electrode, otherwise covered by a lipid bilayer to emulate a cell membrane. The goal of the work is to observe conformation changes in the enzyme as a result of electron transfer; such changes are hypothesized to be an essential feature of efficient biological electron transfer processes.