Electron Transfer in Structurally Engineered Metalloproteins

该项目由无机，生物无机和 器官计划，是为了继续研究的 影响生物体内长程电子转移的因素 系统. 酵母基因工程突变体 组氨酸残基被取代异-1-细胞色素c 对于天然氨基酸在外周上的各个位点， 蛋白质将用于这些研究。 引入 氧化还原活性的发光钌络合物，通过络合作用 在这些组氨酸位点，允许光谱分析 电子转移到金属酶或从金属酶转移的监测 在众所周知的固定距离上 最近开发的激光器 将使用闪蒸淬火技术来确定 电子转移速率 这项技术有两个主要的 这些研究优于以前的方法。 一是 允许研究蛋白质与天然铁，而不是 而不是金属替代版本，第二，它允许 研究范围更广的传输速率。 在第二 在研究的第一阶段，类似地修饰的人类肌红蛋白将 用于单电子耦合的研究 转移到多电子事件，如产生 铁基（Fe=O）物种。 这些研究的总体目标是 是为了确定电子从 施主到受主的距离为10埃， 更大 %%% 电子转移是分子生物学中最重要的过程之一， 生物系统。 这些电子的一个有趣的方面 转移的关键是电子供体和受体 常常相隔很远。 然而， 短距离的电子转移，其中供体的重叠 和受体轨道可以发生，是发达的， 电子长距离移动的机制是 没有很好地理解。 像这样的研究最终可能 从而更好地治疗某些生理疾病 以及太阳能转换的新方法。

This project, supported by the Inorganic, Bioinorganic and Organometallic Program, is for continuation of studies of the factors that affect long-range electron transfer in biological systems. Genetically engineered mutants of yeast iso-1-cytochrome c, which have histidine residues substituted for the native amino acid at various sites on the periphery of the protein, will be used for these studies. Introduction of redox active, luminescent ruthenium complexes, by complexation at these histidine sites, allows for the spectroscopic monitoring of electron-transfer to, or from, the metalloenzyme over well-known, fixed distances. A recently developed laser flash-quench technique will be used to determine the electron-transfer rates. This technique has two major advantages for these studies over previous methods. First, it allows for study of the protein with the native iron, rather than a metal substituted version, and second, it permits the study of a much wider range of transfer rates. In a second phase of the research, similarly modified human myoglobins will be used for the study of the coupling of single electron transfers to multielectron events such as generation of a ferryl (Fe=O) species. The overall objective of these studies is to determine the mechanism by which the electron moves from the donor to the acceptor over distances of 10 angstroms and greater. %%% Electron transfer is one of the most important processes in biological systems. An intriguing aspects of these electron transfers is that the electron donor and acceptor are frequently separated by large distances. Whereas theories of electron transfer over short distances, where overlap of donor and acceptor orbitals can occur, is well developed, the mechanism by which the electron moves over long distances is not well understood. Studies such as these may ultimately result in better treatment of certain physiological disorders and in new methods of solar energy conversion.