VIBRATIONAL STUDIES OF METAL CLUSTERS IN PROTEINS

蛋白质中金属簇的振动研究

• 批准号: 2185841
• 负责人: ROMAN S CZERNUSZEWICZ
• 金额: $ 9.02万
• 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/2185841
• 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.

锰是生物体发挥作用所必需的微量元素 双氧的各种氧化还原转化。 一个新的计划将是 开发用于探索结构和反应性的基本问题 利用光谱法确定生物系统的锰活性位点 方法，特别是共振拉曼（RR）光谱。 初步目标 将包括超氧化物歧化酶 (SOD) 的单核 Mn(III) 位点 和双核非血红素锰过氧化氢酶，其中有几种可能的 结构已被提出。 我们的方法是获得 蛋白质和精心选择的模型的高质量 RR 谱 配合物，借助低温拉曼技术和变量 激发波长，并记录尽可能多的频率和同位素 尽可能地转变。 然后将进行正常模式计算， 基于结构特征的锰仿生模型系统， 开发物理上合理的力场的目标是 准确地再现观察到的频率和同位素位移 详细了解所监测的振动模式的性质。 RR 和溶液 FT-IR 光谱将用于阐明 超氧化物单核金属位点的阴离子相互作用模式 通过探测 Cu、Zn-、Fe- 和的配体振动来检测歧化酶 含锰SOD-叠氮化物加合物。 精氨酸残基（Arg [141] 叠氮化物结合的化学修饰和磷酸盐加成 振动频率将用于深入了解 SOD 催化过程中的 Arg 141。 对本质的理解 被监测的振动模式将允许确定结构 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。