INTERMEDIATE DURING ASSEMBLY OF RIBONUCLEOTIDE REDUCTASE R2 COFACTOR

我们建议研究一种中间体的结构， 在必需酪氨酸的组装过程中产生 核糖核酸R2亚基的自由基/二铁簇协因子 从大肠杆菌中提取的还原酶。斯塔布和他的同事已经证明了 这种具有运动能力的中间体(称为X)可以产生 酪氨酸基的快速冷冻淬火(RFQ)穆斯堡尔谱和电子顺磁共振 与停流吸收相结合的光谱分析 光谱学。由于可以制成含有60-80%X的RFQ样品， 我们建议使用RFQ EXAFS来区分这两者 结构主题。这些结构性信息将提供洞察力 深入到组装过程的机制中，并扩大我们的 了解双核铁蛋白对氧的激活作用。

We are proposing to study the structure of an intermediate that is generated during the assembly of the essential tyrosyl radical/diferric cluster cofactor of the R2 subunit of ribonucleotide reductase from E coli. Stubbe and coworkers have demonstrated that this kinetically competent intermediate (called X) can generate the tyrosyl radical using rapid freeze quench (RFQ) Mvssbauer and EPR spectroscopies in conjunction with stopped flow absorption spectroscopy. Since RFQ samples can be made that consist of 60-80% X, we propose to use RFQ EXAFS to distinguish between these two structural motifs. This structural information will provide insight into the mechanism of the assembly process and broaden our understanding of oxygen activation by dinuclear iron proteins.