Structural Studies of Fe:S Proteins: Nitrogenase, Rubredoxin and Ferredoxin

蛋白质中的铁-硫（Fe：S）中心表现出多种多样的铁-硫结合。 结构和功能特性。 x射线衍射方法 将被用来确定三个的三维结构， 参与电子转移反应的Fe：S蛋白质： 棕色固氮菌固氮酶铁蛋白， 超嗜热菌Pyrococcus的红氧还蛋白和铁氧还蛋白 骨质疏松症 晶体结构将允许 多肽和铁硫中心作用的评价 在控制氧化还原性质和电子转移方面 这些蛋白质的机制。 具体结构目标 该建议包括： 固氮酶-铁蛋白。 钼铁（MoFe-） 固氮酶的蛋白质组分含有底物位点 还原，一种目前未知的铁-硫-钼辅因子 结构 簇和蛋白质的功能作用将 通过晶体学研究，至少达到2.5A 决议的A. vinelandii MoFe-蛋白的存在下， 不存在结合的配体（抑制剂和核苷酸）， 不同的氧化态：突变的MoFe-蛋白质; 与MoFe蛋白相关的替代固氮酶蛋白。 耐热红氧还蛋白和铁氧还蛋白。 古细菌 热球菌是一种超嗜热菌，生长在1000 ℃。 Rubredoxin的晶体结构（精制至至少 0.96A分辨率）和铁氧还蛋白不仅 定义蛋白质-Fe：S中心相互作用的细节，但是 还将提供一个结构框架， 这些蛋白质的热稳定性。

Iron-sulfur (Fe:S) centers in proteins exhibit a diverse range of structures and functional properties. X-ray diffraction methods will be used to determine the three-dimensional structures of three Fe:S proteins involved in electron transfer reactions: the nitrogenase molybdenum-iron protein from Azotobacter vinelandii and the rubredoxin and ferredoxin from the hyperthermophile Pyrococcus furiosis. The crystallographic structures will permit an evaluation of the roles of the polypeptide and iron-sulfur centers in controlling the redox properties and electron transfer mechanisms of these proteins. The specific structural objectives of this proposal are: Nitrogenase molybdenum-iron protein. The molybdenum iron (MoFe-) protein component of nitrogenase contains the site of substrate reduction, an iron-sulfur-molybdenum cofactor of presently unknown structure. The functional roles of the clusters and protein will be addressed by crystallographic studies to at least 2.5A resolution of the A. vinelandii MoFe-protein in the presence and absence of bound ligands (inhibitor and nucleotides) and in different oxidation states: mutant MoFe-proteins; and structures of alternative nitrogenase proteins related to MoFe-protein. Thermostable rubredoxin and ferredoxin. The archaebacterium Pyrococcus furiosis is a hyperthermophile that grows at 1000C. Crystallographic structures of the rubredoxin (refined to at least 0.96A resolution) and ferredoxin from this organism will not only define the details of the protein-Fe:S center interactions, but will also provide a structural framework for characterizing the thermostability of these proteins.