NOVEL REDOX PROTEINS FROM SULFATE REDUCING BACT

来自硫酸盐还原菌的新型氧化还原蛋白

• 批准号: 3306756
• 负责人: Boi-Hanh V. Huynh
• 金额: $ 12.61万
• 依托单位: EMORY UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1992
• 资助国家: 美国
• 起止时间: 1992-09-30 至 1996-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3306756
• 关键词: Desulfovibrio; Mossbauer spectrometry; bacterial proteins; electron spin resonance spectroscopy; iron compounds; metal complex; metalloproteins; oxidation reduction reaction; protein structure function

Three novel non-heme iron proteins have been isolated recently from sulfate reducing bacteria of the Desulfovibrio genus. They are: (1) desulfoferrodoxin, a monomer containing a distorted FeS4 center (center I) and an octahedrally coordinated iron center with N- and O-containing ligands (center II), (2) rubrerythrin, a dimer containing two rubredoxin-like FeS4 centers and one (may be two) mu-oxo bridged diiron cluster, and (3) isadoxin (tentatively named after Dr. Isabel Moura who discovered this protein), a monomer containing probably two redox active iron-sulfur clusters of unknown structure. This proposal is focused on the EPR and Mossbauer studies of these proteins and is an essential part of a larger, inter-laboratory research program aiming to elucidate the structure and functions of metalloproteins isolated from sulfate and nitrate reducing bacteria. The objective of this proposal is to gain structural information of the above mentioned iron centers through spectroscopic investigations. By correlating these spectroscopic results with the biological and biochemical properties to be obtained by our collaborators, we hope to acquire functional information of these interesting proteins. Certain sulfate reducing bacteria are known to be responsible for the degradation of organic matter in anaerobic marine environment. The enzyme which catalyzes the anaerobic degradation of aromatic compounds, however, has not get been found. It is therefore interesting to note that center II in desulfoferrodoxin exhibits spectroscopic properties similar to those of dioxygenases. Consequently, for the studies of desulfoferrodoxin, emphasis is on center II. The proposed experiments are specifically designed to probe the ligand environment of center II and to investigate its interaction with aromatic organic compounds and small ligands. For rubrerythrin, our focus will be on the diiron cluster. It is now realized that the mu-oxo bridged diiron cluster is involved in the catalysis of a variety of important biological functions, including oxygen transport, methane hydroxylation, phenol oxidation, and hydrolysis of phosphate esters. A specific goal of this proposed program is to obtain detailed spectroscopic characterization and to probe the ligand environment of the diiron cluster in rubrerythrin. The results should enhance our knowledge on the physical properties and coordination chemistry of this versatile biological motif. For isadoxin, our objective is to gain structural information and to obtain detailed electronic and magnetic properties of the unusual iron clusters. Our preliminary studies suggest that at least one (if not both) of the clusters is probably a 6Fe cluster with mixed S, 0, and/or N ligands, a unique structure that has never been reported previously, neither for proteins nor for model compounds. Consequently, results obtained from the proposed measurements are expected to stimulate new developments in the research of iron-sulfur proteins.

最近从其中分离出三种新型非血红素铁蛋白 脱硫弧菌属的硫酸盐还原菌。 他们是：（1） 脱硫铁氧还蛋白，一种含有扭曲的 FeS4 中心（中心 I) 和含 N 和 O 的八面体配位铁中心 配体（中心 II），（2）红红菊酯，含有两个的二聚体 红氧还蛋白样 FeS4 中心和一个（可能是两个）mu-氧桥联铁 簇，以及 (3) isadoxin（暂以 Isabel Moura 博士命名，他 发现了这种蛋白质），可能含有两个氧化还原活性的单体 结构未知的铁硫簇。 该提案的重点是 EPR 和 Mossbauer 对这些蛋白质的研究是重要的一部分 一个更大的实验室间研究计划，旨在阐明 从硫酸盐中分离出的金属蛋白的结构和功能 硝酸盐还原菌。 该提案的目标是获得 上述铁中心的结构信息通过 光谱研究。 通过关联这些光谱结果 具有我们要获得的生物和生化特性 合作者，我们希望获得这些功能信息 有趣的蛋白质。 已知某些硫酸盐还原菌是造成 厌氧海洋环境中有机物的降解。 这 催化芳香族化合物厌氧降解的酶， 然而，尚未被发现。 因此值得注意的是 脱硫铁氧还蛋白的中心 II 表现出光谱特性 与双加氧酶类似。 因此，对于研究 脱硫铁氧还蛋白，重点是中心 II。 拟议的实验 专门设计用于探测中心 II 的配体环境 并研究其与芳香族有机化合物的相互作用 小配体。 对于红红菊酯，我们的重点将放在二铁簇上。 现在是 意识到 mu-oxo 桥接的二铁簇参与了 催化多种重要的生物功能，包括 氧传输、甲烷羟基化、苯酚氧化和水解 磷酸酯。 该拟议计划的一个具体目标是 获得详细的光谱表征并探测配体 红红菊酯中二铁簇的环境。 结果应该 增强我们对物理特性和协调性的了解 这种多功能生物主题的化学。 对于 isadoxin，我们的目标是获得结构信息并 获得不寻常铁的详细电子和磁性特性 集群。 我们的初步研究表明至少有一个（如果不是的话） 两个）簇可能是混合有 S、0 和/或 N 的 6Fe 簇 配体，一种以前从未报道过的独特结构， 既不适用于蛋白质，也不适用于模型化合物。 因此，结果 从拟议的测量中获得的结果预计将刺激新的 铁硫蛋白研究进展.