VIBRATIONAL STUDIES OF METAL CLUSTERS IN PROTEINS

蛋白质中金属簇的振动研究

• 批准号: 2185842
• 负责人: ROMAN S CZERNUSZEWICZ
• 金额: $ 9.34万
• 依托单位: UNIVERSITY OF HOUSTON
• 依托单位国家: 美国
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-01-01 至 1997-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2185842
• 关键词: Raman spectrometry; active sites; adduct; arginine; copper; electronic spectra; enzyme structure; infrared spectrometry; interferometry; iron compounds; manganese; metal complex; protein structure function; superoxide dismutase; zinc

Manganese is an essential trace element in living organisms to perform various redox transformations of dioxygen. A new program will be developed to explore fundamental questions of structure and reactivity at manganese active sites of biological systems by using spectroscopic methods, particularly resonance Raman (RR) spectroscopy. Initial targets will include the mononuclear Mn(III) site of superoxide dismutases(SODs) and dinuclear non-heme Mn-catalases for which several plausible structures have been proposed. Our approach will be to obtain high-quality RR spectra of proteins and of judiciously chosen model complexes, with the aid of low-temperature Raman techniques and variable excitation wavelengths, and to record as many frequencies and isotope shifts as possible. Normal mode calculations will then be carried out, based on structurally characterized Mn biomimetic model systems, with the aim of developing physically plausible force fields capable of reproducing the observed frequencies and isotope shifts accurately and to understand in detail the nature of vibrational modes being monitored. The RR and solution FT-IR spectroscopies will be used to elucidate the anion interaction modes at the mononuclear metal sites of superoxide dismutases by probing ligand vibrations of the Cu,Zn-, Fe-, and Mn-containing SOD-azide adducts. The effects of arginine residue (Arg 141) chemical modification and phosphate addition on azide-bound vibrational frequencies will be used to provide insights into the role of Arg 141 in the SOD catalytic process. An understanding of the nature of the vibrational modes being monitored will allow to pin down structural features of these important enzymes, and to establish protein structural changes associated with the chemistry of their active metal sites.

锰是活生物体的必不可少的痕量元素 二氧化物的各种氧化还原转化。 一个新程序将是 开发以探讨结构和反应性的基本问题 通过使用光谱学的生物系统活性位点 方法，特别是共振拉曼（RR）光谱法。 初始目标 将包括超氧化物歧化酶（SOD）的单核Mn（III）位点 和二核非血红素MN-catalases，其中几个合理 已经提出了结构。 我们的方法是获得 蛋白质的高质量RR光谱和明智选择的模型 复合物，借助低温拉曼技术和可变 激发波长，并记录尽可能多的频率和同位素 尽可能移动。 然后将进行正常模式计算，然后进行 基于结构表征的Mn仿生模型系统， 开发能够有理由的力场的目的 重现观察到的频率和同位素移动的准确移动 详细了解要监视的振动模式的性质。 RR和溶液FT-IR光谱将用于阐明 超氧化物的单核金属位点的阴离子相互作用模式 通过探测Cu，Zn-，Fe-和 含Mn的Sod-Azide加合物。 精氨酸残基的作用（arg 141）在叠氮化物结合的化学修饰和磷酸盐添加 振动频率将用于提供有关该作用的见解 在SOD催化过程中ARG 141。 对本质的理解 监视的振动模式将允许固定结构 这些重要酶的特征，并建立蛋白质结构 与其活性金属位点的化学性质相关的变化。