A New Voltammetric Strategy for Investigating Reactive Iron-Sulfur Clusters

研究活性铁硫簇的新伏安策略

• 批准号: 9118772
• 负责人: Fraser Armstrong
• 金额: $ 27万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-06-01 至 1994-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9118772&HistoricalAwards=false
• 关键词: New; Voltammetric; Strategy; Investigating; Reactive

The aim of this study is to quantify complex reactivities of Fe-S clusters in proteins. These clusters perform numerous, diverse functions in nature. A novel methodology will be used, exploiting the unmediated voltammetry displayed by ferredoxins (small proteins containing one or two clusters) at graphite electrodes in the presence of aminocyclitols. Ferredoxins co-adsorb with aminocyclitols forming electroactive films. This makes possible highly economical, detailed studies involving film transfer between electrolytes containing reagents that react with Fe-S clusters. Cluster oxidation levels are controlled, and reactions are monitored via voltammetric signals assigned to specific states by EPR and MCD spectroscopy. Some longstanding problems of studying reactions of Fe-S clusters - very low reduction potentials, poor spectroscopic signatures, instability and lability - are overcome. Dr. Armstrong will characterize an unusual property of (3Fe-4S) clusters, the ability to undergo reversible, multiple electron and proton uptake. This property represents a dramatic departure from the current belief that the protein environment permits only very conservative changes in cluster oxidation level. He will examine the equilibria and kinetics of reversible metal ion uptake by (3 Fe-4S) to give (M3Fe-4S) in various proteins. The likely existence of clusters containing such ions as Zn will be assessed. He will compare the redox and ligand binding properties of various (M3Fe- 4S) clusters. He will study the course of cluster assembly in proteins, from trace levels of Fe and S, and examine the fidelity of this process in the presence of competing ions such as Zn. %%% This study, exploring the characteristics of this important class of compounds, will help to enlarge our understanding of oxidation -reduction and electron transfer in life processes.

本研究的目的是量化铁硫复合反应性 蛋白质中的簇。 这些集群执行许多不同的 在自然界中的功能。 将使用一种新的方法， 铁氧还蛋白（小蛋白）显示的非介导伏安法 含有一个或两个团簇）在石墨电极上， 氨基环醇的存在。 铁氧还蛋白与 形成电活性膜的氨基环醇。 这使得可以 非常经济，详细的研究，涉及电影之间的转移 含有与Fe-S簇反应的试剂的电解质。 簇氧化水平得到控制，反应得到控制 通过指定给特定状态的伏安信号进行监测， EPR和MCD光谱。 几个长期存在的研究问题 Fe-S簇合物的反应-非常低的还原电位， 光谱特征、不稳定性和不稳定性-被克服。 阿姆斯特朗博士将描述（3Fe-4S）的一种不寻常性质。 团簇，进行可逆的，多电子和 质子摄取 这一特性代表了一种戏剧性的背离， 目前认为，蛋白质环境只允许非常 簇氧化水平的保守变化。 他将审查 可逆金属离子吸收的平衡和动力学（3 Fe-4S）以在各种蛋白质中产生（M3 Fe-4S）。 可能存在的 将评估含有诸如Zn的离子的簇。 他将 比较各种（M3 Fe- 4S）簇。 他将于一九九九年修读集团组装课程。 蛋白质，从微量的铁和硫，并检查保真度 在竞争离子如Zn的存在下， %%% 本研究探讨了这一重要班级的特点 化合物，将有助于扩大我们对氧化的理解 - 生命过程中的还原和电子转移。