INFRARED STUDY OF OXIDASE DYNAMICS

所有时间尺度上蛋白质动力学的时间分辨红外(TRIR)研究 提出了从亚皮秒到秒的时间间隔。这一行动的主要目标 研究对象是哺乳动物和细菌中的细胞色素氧化酶。一些工作是在 建议肌红蛋白和血红蛋白建立技术可行性或 来模拟更复杂的氧化酶。长期目标是 了解氧化酶的结构细节和功能动力学， 地球上所有的有氧生命都依赖于它。技术目标是 发展新的和普遍适用的蛋白质研究方法 动力学，基于红外线对结构特征的观察 对于其他光谱探测器来说是不可见的。一套TRIR 将使用的技术：亚皮秒至皮秒的光学延迟方法 纳秒动力学；从纳秒到 秒.直接测定用时间分辨红外线线性二色性 红外活性结构与电子结构的相对取向 偶极子和步进扫描时间分辨公平用于观察瞬变 整个红外光谱上的现象。这些研究将是 在适当的情况下辅以瞬变电子能谱，时间- 分辨磁性圆二色谱和时间分辨共振拉曼光谱 调查。将进行的具体研究包括：(1)TRIR 结扎动力学的研究，包括 血红素键配体的光解离/复合，配体的去向 光解离、与非血红素金属的结合和动力学依赖性 基于立体和电子因素。结果将会详细说明。 对O2位的配位和立体现象的理解 激活。(2)内源蛋白质IR发色团的TRIR研究， 包括氨基酸侧链、肽骨架和假体 组。结果将阐明蛋白质结构的反应 以及对连接和氧化还原扰动的构象。(3)时间分辨 红外线性二色性，结合以上(1)和(2)研究， 旨在确定在以下情况下发生的特定结构重新定向 短时间尺度的动态。

Time-resolved infrared (TRIR) studies of protein dynamics on all timescales from subpicosecond to seconds are proposed. The primary targets of this study are cytochrome oxidases from mammals and bacteria. Some work on myoglobin and hemoglobin is suggested to establish technical feasibility or to model the more complicated oxidases. The long-term goal is to understand in structural detail the functional dynamics of the oxidases, upon which all aerobic life on earth depends. A technical objective is to develop new and generally applicable approaches to the study of protein dynamics, based upon the observation by infrared of structural features that are invisible to other spectroscopic probes. A suite of TRIR techniques will be used: optical delay methods for subpicosecond to nanosecond dynamics; real-time TRIR for dynamics from nanoseconds to seconds; time-resolved infrared linear dichroism for direct determination of the relative orientation of infrared-active structures and electronic dipoles, and step-scan time-resolved FAIR for observation of transient phenomena over the entire infrared spectrum. These studies will be supplemented where appropriate by transient electronic spectroscopy, time- resolved magnetic circular dichroism, and time-resolved resonance Raman investigations. Specific studies to be performed include: (1) TRIR investigation of ligation dynamics, including photodissociation/recombination of heme-bond ligands, fate of ligands after photodissociation, binding to nonheme metals, and dependence of dynamics upon steric and electronic factors. The result will be detailed understanding of ligation and steric phenomena at the site of O2 activation. (2) TRIR studies of endogenous protein IR chromophores, including amino acid side chains, the peptide backbone and prosthetic groups. The results will elucidate the response of the protein structure and conformation to ligation and redox perturbations. (3) Time-resolved infrared linear dichroism, studied in connection with (1) and (2) above, aimed at determining specific structural reorientations which occur during the short-timescale dynamics.