IRON AND MOLYBDENUM COMPLEXES: ENZYME ACTIVE SITES

该建议涉及合成，结构， 特定Fe/M/S的光谱和反应性质 （M=Mo，V，W），Fe/S和Mn/O络合物。 这些化合物 预期分别用作 固氮酶中的Fe/M/S中心，固氮酶中的Fe 2S 2中心。 Rieske蛋白和水氧化所必需的Mn 4簇 在光合作用中。 金属中心的重要性 金属蛋白和金属酶功能良好 认可. 生物化学的氧化和还原 在含金属的活性位点处发生的基质， 与生命维持过程密切相关。 固氮酶Fe/M/S中心的合成类似物（M=Mo，V） 将获得具有Fe/M/S特征的， 与固氮酶相似的特性。 一个成功 固氮酶活性位点的类似物应允许 生物催化转化（还原） 二氮转化为氨 该反应也可能用于 我们对金属激活小分子的理解 综合体一般。 合成专门设计的 类似物复合物的Fe 2S 2，Rieske蛋白质中心将是 重要的是确定影响因素， 这些中心的氧化还原电位。 十肽的合成 Fe_2S_2中心的络合物也将被进行。 的 十肽配体被设计为提供氨基酸残基 被认为存在于Rieske蛋白中。 比较 光谱研究有望提供有用的信息 关于Rieske蛋白质中心 很少有人知道 参与水氧化的Mn 4中心的结构 在光合作用过程中。 基本协调研究 化学的低聚锰簇需要之前， 设计Mn中心的特定类似物络合物， 光系统II

This proposal is concerned with the synthesis, structures, spectroscopic, and reactivity properties of specific Fe/M/S (M=Mo, V,W), Fe/S and Mn/O complexes. These compounds respectively are expected to serve as synthetic analogs for the Fe/M/S centers in the nitrogenases, the Fe2S2 centers in the Rieske proteins and the Mn4 cluster essential for water oxidation in photosynthesis. The great importance of metal centers in the function of metalloproteins and metalloenzymes is well recognized. The biochemical oxidation and reduction of substrates that occurs at metal containing active sites is intimately involved with crucial life sustaining processes. Synthetic analogs for the Fe/M/S center in nitrogenase (M=Mo, V) will be obtained with a Fe/M/S features, and spectroscopic characteristics similar to those in nitrogenase. A successful analog for the nitrogenase active site should allow for an understanding of the biological catalytic conversion (reduction) of dinitrogen to ammonia. This reaction also is potentially useful for our understanding of small molecule activation by metal complexes in general. The synthesis of specifically designed analog complexes for the Fe2S2, Rieske protein center will be important for the identification of the factors that affect the redox potentials of these centers. The synthesis of a decapeptide complex of the Fe2S2 center also will be carried out. The decapeptide ligand is designed to supply the amino acid residues thought to be present in the Rieske proteins. Comparative spectroscopic studies are expected to provide useful information regarding the Rieske protein centers. Very little is known about the structure of the Mn4 center involved in the oxidation of water during photosynthesis. Studies of the basic coordination chemistry of oligonuclear Mn clusters are needed prior to the design of specific analog complexes for the Mn center in photosystem II.