"Collaborative Research" Chemical & Genetic Modification of Biological Iron-Sulfur Clusters: Azotobacter Vinelandii Ferredxin I

铁硫（Fe-S）蛋白含有由 主要是Fe、S2-和半胱氨酸残基。 这些 蛋白质普遍存在于所有已知的生物体中， 是每一个重要生物过程的核心 三 分别含有1、2和4个Fe的簇合物类型 原子现在已经被很好地表征， 含有三个Fe原子的铁。 第一 三个显示多个氧化水平。 它最近 已经表明电子传输不是唯一的功能 这些蛋白质。 现在很清楚， Fe-S团簇结构的种类比以前更多 它得到了认可，并继续扩大。 化学反应很远 比简单的、可逆的单电子氧化还原更广泛 行为 本提案的目的是确定 主序列确定哪种类型的集群是 在特定的蛋白质中起作用。 为了实现这一目标， 蛋白质结合的3FE和4FE的结构和反应性 （Fe-S）团簇在A. vinelandii fereedoxin I（AVFD） 深入研究。 这种小蛋白质非常适合 这样的调查，因为它表达了多种形式和X- 射线数据变得可用。 因此，计划 为了纯化和结晶三种新形式的AvFdI， 对它们进行物理化学表征， 定向诱变，并纯化和表征 产生铁氧还蛋白。 这项工作可能对我们的 探索了解固氮酶和其他多中心氧化还原 含有Fe-S中心的蛋白质。 强烈支持 高度优先推荐。

Iron sulfur (Fe-S) proteins contain clusters composed predominately of Fe, S2- and cysteine residues. These proteins are ubiquitous occuring in all known organisms and are central to every essential biological process. Three types of clusters containing respectively, 1, 2, and 4 Fe atoms are now well characterized and recently clusters containg three Fe atoms have been discovered. The first three exhibit multiple oxidation levels. It has recently been shown that electron transport is not the sole function of these proteins. It is now abundantly clear that the variety of Fe-S cluster structures is greater than previously recognized and continues to expand. The chemistry is far more extensive than simple, reversible one-electron redox behavior. The goal of this proposal is to ascertain how the primary sequence determines which type of cluster is functional in a given protein. To achieve this goal the structures and reactivities of protein-bound 3 FE and 4 FE (Fe-S) clusters in A. vinelandii fereedoxin I (AVFD) will be studied in depth. This small protein is ideally suited for such an investigation, as it expresses multiple forms and X- ray data is becoming available. Consequently, it is planned to purify and crystallize the three new forms of AvFdI, characterize them physico-chemically, modify them by site directed mutagenesis, and purify and characterize the resulting fereedoxins. This work may prove crucial to our quest to understand nitrogenase and other multicentered redox proteins containing Fe-S centers. Support is strongly recommended with a high priority.