TIME RESOLVED SPECTROSCOPY OF CYTOCHROME OXIDASES AND PGH SYNTHASES

这个项目的总体目标是了解氧气和过氧化氢。 活化态及其释放自由能的分子机制 这些底物的还原作用与生物用途有关 细胞色素氧化酶和前列腺素H合成酶的化学。NS和PS 时间分辨共振拉曼光谱，时间分辨光学 光谱学，低温FTIR光谱学和电子磁性- 共振技术将成为主要的分析工具。近期 密歇根州立大学使用这些光谱仪的技术进步将使 美国利用它们来研究突变型和野生型细胞色素氧化酶和 前列腺素合成酶。通过细胞色素氧化酶，我们打算表征 质子进入和离开活性中心的路径是 与02减少和质子泵送有关；特定残留物 可能参与金属中心的配体交换过程 将有针对性地研究它们在催化中的作用 周而复始。在这些实验中，我们打算阐明 质子对氧气活化和还原化学的控制 发生在细胞色素氧化酶中，而细胞色素氧化酶 电子转移到活性氧中间体释放的自由能 是用来驱动质子转移的。对于前列腺素合成酶， 将使用时间分辨技术研究过氧化氢的减少 了解反应顺序和与酪氨酸基的偶联 队形。随后的突变分析将针对涉及到的残基 晶体结构对催化是必不可少的。

The overall goal of this project is to understand oxygen and peroxide activation and the molecular mechanisms by which the free energy released in the reduction of these substrates is couple to biologically useful chemistry in cytochrome oxidases and prostaglandin H synthases. Ns and ps time-resolved resonance Raman spectroscopy, time-resolved optical spectroscopy, low-temperature FTIR spectroscopy, and electron magnetic- resonance techniques will be the principal analytical tools. Recent technical advances to Michigan State with these spectroscopies will allow us to use them to study both mutant and wild-type cytochrome oxidase and prostaglandin synthase. With cytochrome oxidase, we intend to characterize pathways for proton conduction in and out of the active site that are relevant to both 02 reduction and proton pumping; specific residues that are potentially involved in ligand exchange processes at the metal centers will be targeted and studied in terms of their functions in the catalytic cycle. In these experiments, we intend to elucidate the means by which proton control of the dioxygen activation and reduction chemistry that occurs in cytochrome oxidase is implemented and the means by which the free energy released by electron transfer to reactive oxygen intermediates is used to drive proton translocation. For prostaglandin synthase, the reduction of peroxides will be studied with time-resolved techniques to understand the reaction sequence and the coupling to tyrosyl radical formation. Subsequent mutation analysis will target residues implicated by the crystal structure as being essential to the catalysis.