INTERMEDIATE DURING ASSEMBLY OF RIBONUCLEOTIDE REDUCTASE R2 COFACTOR

我们建议研究中间体的结构， 在必需酪氨酰的组装过程中产生 核糖核苷酸R2亚基自由基/二铁簇辅因子 还原酶。 Stubbe和他的同事已经证明， 这种具有动力学活性的中间体（称为X）可以产生 用快速冷冻淬灭法（FHT）Mvssbauer和EPR研究酪氨酰自由基 与停流吸收结合的光谱学 谱 由于可以制备由60- 80%X组成的样品， 我们建议使用EXAFS来区分这两者 结构图案 这些结构信息将提供洞察力 进入装配过程的机制，并扩大我们的 了解双核铁蛋白的氧活化作用。

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.