CRYSTALLOGRAPHIC STUDIES OF ELECTRON TRANSFER PROTEINS

氮素的基本生物过程 固定、硝化和光合作用是由 电子转移蛋白的复合体。X射线衍射法 将被用来确定 这些系统中的组成蛋白质。这些建筑将允许 蛋白质辅因子和辅因子辅因子的评价 控制氧化还原性质和电子的相互作用 蛋白质的传递机制；结构相互作用 它们对电子转移的专一性负责 供体和受体蛋白之间的关系；以及能量机制 与电子转移偶联相关的转导 ATP水解(固氮酶)和光吸收(光合作用)。 这些领域的具体结构目标是： 1.固氮酶。生物固氮的催化作用是由 固氮酶复合体，由铁(Fe-)蛋白和 钼铁(MoFe-)蛋白。三维结构 棕色固氮菌和梭状芽孢杆菌铁蛋白的研究 巴氏杆菌将会完成。铁蛋白的结构- 铁蛋白Will的核苷酸复合体和定点突变体 被确定为描述电子转移的机制，以及 三磷酸腺苷水解与这一过程的耦合。共结晶化 铁-蛋白质络合物的结构测定 通过生理电子转移伙伴MoFe-Protein， 将尝试铁氧还蛋白和黄曲霉毒素。 2.光合作用反应中心(RC)。改进了 红杆菌细菌光合作用RCS的结构 球状芽孢杆菌R-26和2.4.1菌株将完成。构筑物 不同氧化状态的RCS，来自定点突变体， 而在低温条件下将被确定为提供 理解电子效率的结构基础 在这个系统里转账。RB的结构。球状线虫 细胞色素c2，作为细胞色素c2的生理还原剂 氧化RC将被测定，并共结晶的 将尝试细胞色素-RC复合体。作为唯一的班级 已知原子结构的膜蛋白，RC的分析 还将重点介绍膜蛋白的一般含义 结构。 3.硝化作用。四氢血红素细胞色素c-554的结构， 参与亚硝化单胞菌的硝化反应 要下定决心。晶体的结晶和结构测定 将尝试从该生物体中提取羟胺氧化还原酶。

The fundamental biological processes of nitrogen fixation, nitrification and photosynthesis are catalyzed by complexes of electron transfer proteins. X-ray diffraction methods will be used to determine the three-dimensional structures of the component proteins in these systems. The structures will permit an evaluation of the protein - cofactor and cofactor - cofactor interactions that control the redox properties and electron transfer mechanisms of the proteins; the structural interactions that are responsible for the specificity in electron transfer between donor and acceptor proteins; and the mechanisms of energy transduction associated with the coupling of electron transfer to ATP hydrolysis (nitrogenase) and light absorption (photosynthesis). The specific structural objectives in these areas are: 1.Nitrogenase. Biological nitrogen fixation is catalyzed by the nitrogenase complex, which consists of iron (Fe-) protein and molybdenum iron (MoFe-) protein. The three-dimensional structures of Fe-protein from Azotobacter vinelandii and Clostridium pasteurianum will be completed. Structures of Fe-protein - nucleotide complexes and site directed mutants of Fe-protein will be determined to describe the mechanism of electron transfer, and the coupling of ATP hydrolysis to this process. Cocrystallizations and subsequent structure determinations of Fe-protein complexed with the physiological electron transfer partners MoFe-protein, ferredoxin and flavodoxin will be attempted. 2.Photosynthetic Reaction Center (RC). Refinement of the structures of the bacterial photosynthetic RCs from Rhodobacter sphaeroides strains R-26 and 2.4.1 will be completed. Structures of RCs in various oxidation states, from site directed mutants, and under low temperature conditions will be determined to provide a structural basis for understanding the efficiency of electron transfer in this system. The structure of the Rb. sphaeroides cytochrome c2 that serves as the physiological reductant for the oxidized RC will be determined, and co-crystallization of the cytochrome - RC complex will be attempted. As the only class of membrane proteins of known atomic structure, analysis of the RC will also focus on general implications for membrane protein structure. 3.Nitrification. The structure of the tetraheme cytochrome c-554, involved in nitrification reactions of Nitrosomonas europea, will be determined. Crystallization and structure determination of hydroxylamine oxidoreductase from this organism will be attempted.