STRUCTURE AND MECHANISM OF FE-S PROTEINS

我们实验室的目标是确定蛋白质结构在 氧化还原反应，特别是那些涉及Fe：S中心的电子 转移 我们选择氮还原作为模型。 虽然优雅 光谱研究已经确定了新的Fe：S和Mo：Fe：S中心， 固氮酶蛋白质，我们只有一个有限的图片的蛋白质 结构 然而，后者无疑会影响 金属中心的性质。 对于固氮酶，没有特定的氨基 酸被认为是电子转移过程的一部分。 只有Fe：S中心的铁蛋白配体已被确定。 它 我们打算用溶液化学方法来研究 蛋白质结构在催化和电子转移过程中的作用。 我们将 将结构变化和化学反应性与光谱 Fe：S蛋白质的性质。 对于拟议的研究，铁蛋白 (Av2)棕色固氮菌固氮酶的钼铁蛋白（Av 1） 被利用 今后五年的具体目标是： 1. 用光谱方法研究了Av 2中Fe：S心的相互转换 和化学改性方法。 2. 从无活性形式中重建酶活性Av 2。 3. 为了鉴定ATP/ADP结合位点的氨基酸残基， 与Fe：S中心的关系。 4. 确定Avl中Fe：S和Mo：Fe：S中心的潜在巯基配体。 5. 确定Av 1和Av 2上形成复合物的结合区域。 6. 确定底物中潜在的催化重要残留物 还原位点。 7. 为了研究“简单的”，光谱定义明确的Fe：S中的硫醇反应性， proteins.

The goal of our laboratory is to determine the role of protein structure in redox reactions, especially those involving Fe:S centers for electron transfer. We have chosen nitrogen reduction as a model. Although elegant spectroscopic studies have identified new Fe:S and Mo:Fe:S centers in nitrogenase proteins, we have only a limited picture of the protein structure. Yet, it is the latter which undoubtedly influences the properties of the metallo centers. For nitrogenase, no specific amino acids have been identified as part of the electron transfer processes. Only the Fe:S center ligands for the Fe-protein have been determined. It is our intention to use solution chemical methods to study changes in protein structure during catalysis and electron transfer. We will correlate the structural changes and chemical reactivity with the spectral properties of Fe:S proteins. For the proposed studies, the Fe-protein (Av2) and MoFe-protein (Av1) from Azotobacter vinelandii nitrogenase will be used. The specific objectives for the next five years are: 1. To study the interconversion of the Fe:S center in Av2 using spectral and chemical modification methods. 2. To reconstitute enzymatically active Av2 from inactive forms. 3. To identify amino acid residues in the ATP/ADP binding site and their relationship to the Fe:S center. 4. To identify potential thiol ligands of Fe:S and Mo:Fe:S centers in Avl. 5. To identify the binding regions on Av1 and Av2 for complex formation. 6. To identify potential catalytically important residues in the substrate reduction site. 7. To study the thiol reactivity in "simple", spectrally well-defined Fe:S proteins.