Mechanistic Studies of Ribonucleotide Reductase

叶史瓦大学阿尔伯特·爱因斯坦医学院的 Gary Gerfen 博士将在化学系生命过程化学项目的奖项中研究核糖核苷三磷酸还原酶的转换和抑制机制。核糖核苷酸还原酶 (RNR) 存在于迄今为止所表征的所有细胞非寄生生物中，并且也由许多 DNA 病毒编码。这些酶催化核苷酸还原为相应的脱氧核糖核苷酸，这是唯一已知的从头生成 DNA 复制和修复前体的方法。尽管最近所有类别 RNR 的研究都取得了重大进展，但关于底物周转、机械抑制剂失活和变构调节机制的问题仍然存在。该奖项的目标是关注最简单的代表性 RNR，即来自莱希曼乳杆菌的核糖核苷三磷酸还原酶 (RTPR)。深入了解这种最简单的核糖核苷酸还原酶的反应机制和变构调节将有助于对这一类重要酶的基本了解。 Gerfen 博士将研究使用核糖核苷酸和活性位点突变体的底物周转机制，以及使用基于机制的抑制剂的抑制和失活机制。最后，将使用室温连续波和低温脉冲位点定向自旋标记电子顺磁共振技术来探测被认为对变构调节重要的 RTPR 区域的结构和动态。核糖核苷酸还原酶是提供几乎所有生物体中制造 DNA 构建块的唯一已知方法的酶。由于 DNA 对细胞功能的各个方面都至关重要，因此这些酶在从细菌到人类的生物体新陈代谢中发挥着重要作用。这些酶的结构和功能缺陷会导致许多疾病，而旨在抑制核糖核苷酸还原酶功能的抗菌和抗癌药物目前已在临床使用。然而，目前尚不清楚灭活这些酶的药物如何发挥作用。格芬博士的工作将使我们更好地了解核糖核苷酸还原酶发挥作用的基本机制。

In this award from the Chemistry of Life Processes Program in the Chemistry Division, Dr. Gary Gerfen, from the Albert Einstein College of Medicine of Yeshiva University, will investigate the mechanism of turnover by and inhibition of the enzyme ribonucleoside triphosphate reductase. Ribonucleotide reductases (RNRs) are present in all cellular non-parasitic organisms characterized to date, and are also encoded by many DNA viruses. These enzymes catalyze the reduction of nucleotides to the corresponding deoxyribonucleotides, the only known means of de novo generation of precursors for both DNA replication and repair. Despite significant progress being made in the study of all classes of RNR recently, questions remain regarding mechanisms of substrate turnover, inactivation by mechanistic inhibitors and allosteric regulation. The objective of this award is to focus on the simplest representative RNR, ribonucleoside triphosphate reductase (RTPR) from Lactobacillus leichmannii. Gaining insight into the reaction mechanism and allosteric regulation of this simplest of the ribonucleotide reductases will contribute to basic understanding of this important class of enzymes. Dr. Gerfen will investigate the mechanism of substrate turnover using ribonucleotides and active site mutants, and the mechanism of inhibition and inactivation using mechanism-based inhibitors. Finally, the structure and dynamics of regions of RTPR thought to be important for allosteric regulation will be probed using room temperature continuous wave and low temperature pulsed site directed spin label electron paramagnetic resonance techniques.Ribonucleotide reductases are enzymes that provide the only known way to make the building blocks of DNA in almost all organisms. Because DNA is crucial to every aspect of cellular function, these enzymes play an essential role in the metabolism of organisms from bacteria to humans. Defects in the structure and function of these enzymes lead to many diseases, and antibacterial and anticancer drugs designed to inhibit the function ribonucleotide reductases are currently in clinical use. However, it is not understood how the drugs that inactivate these enzymes function. Dr. Gerfen's work will give us better understanding of the basic mechanisms by which ribonucleotide reductases function.