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: 3306758
• 负责人: Boi-Hanh V. Huynh
• 金额: $ 13.12万
• 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/3306758
• 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.

最近已经分离出三种新型的非血红素铁蛋白 硫酸盐还原细菌的细菌。 他们是：（1） 去甲氟二毒素，一种包含扭曲的FES4中心的单体（中心） i）和一个含n和o的八面体协调的铁心中心 配体（中心II），（2）rubreryThrin，一个二聚体，包含两个 Rubredoxin样FES4中心，一个（可能是两个）Mu-oxo桥接二龙 簇和（3）Isadoxin（以伊莎贝尔·穆拉（Isabel Moura）博士的名字命名 发现了这种蛋白质），一种可能包含两个氧化还原活性的单体 未知结构的铁硫簇。 该提议的重点是 这些蛋白质的EPR和Mossbauer研究是必不可少的部分 旨在阐明的更大的实验室研究计划 从硫酸盐分离的金属蛋白的结构和功能 硝酸盐还原细菌。 该提议的目的是获得 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 使用我们的生物学和生化特性 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细菌是造成的 厌氧海洋环境中有机物的降解。 这 酶的酶催化芳香族化合物的厌氧降解， 但是，尚未找到。 因此很有趣 Deulfoferrodoxin中的该中心II具有光谱特性 与二氧酶类似。 因此，为了研究 去甲氟氟毒素，重点是II中心。 提出的实验 专门设计用于探测中心II的配体环境 并研究其与芳香有机化合物的相互作用， 小配体。 对于RubreryThrin来说，我们的重点将放在二龙群上。 现在 意识到Mu-oxo桥接的二龙簇参与了 催化各种重要的生物学功能，包括 氧运输，甲烷羟基化，苯酚氧化和水解 磷酸酯。 该提议的计划的一个具体目标是 获得详细的光谱表征并探测配体 RubreryThrin中的Diiron群集的环境。 结果应该 增强我们对物理特性和协调的知识 这种多功能生物学基序的化学。 对于Isadoxin，我们的目标是获取结构信息和 获得异常铁的详细电子和磁性 集群。 我们的初步研究表明至少一个（如果没有 两者）群集可能是一个6FE簇，具有混合S，0和/或N 配体是一种以前从未报道过的独特结构， 既不适合蛋白质也不适用于模型化合物。 因此，结果 预计从提出的测量结果将刺激新的 铁硫蛋白研究的发展。