Mechanistic Studies of Ribonucleotide Reductase

在这个由化学学部生命过程化学项目颁发的奖项中，来自叶史瓦大学阿尔伯特·爱因斯坦医学院的Gary Gerfen博士将研究核糖核苷三磷酸还原酶的转化机制和抑制作用。核糖核苷酸还原酶（RNRs）存在于迄今已知的所有细胞性非寄生生物中，也被许多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DNA复制和修复前体从头生成的唯一已知方法。尽管最近对所有类型RNR的研究取得了重大进展，但关于底物转换、机械抑制剂失活和变构调节的机制仍然存在问题。这个奖项的目的是集中在最简单的代表性RNR，核糖核苷三磷酸还原酶（RTPR）从莱希曼乳杆菌。深入了解这种最简单的核糖核苷酸还原酶的反应机理和变构调节将有助于对这类重要酶的基本认识。Gerfen博士将研究使用核糖核苷酸和活性位点突变体的底物转换机制，以及使用基于机制的抑制剂的抑制和失活机制。最后，利用室温连续波和低温脉冲位置定向自旋标记电子顺磁共振技术对RTPR中被认为对变构调节重要的区域的结构和动力学进行探测。核糖核苷酸还原酶是在几乎所有生物体中提供唯一已知的制造DNA构建块的酶。由于DNA对细胞功能的各个方面都至关重要，这些酶在从细菌到人类的生物体代谢中起着至关重要的作用。这些酶在结构和功能上的缺陷导致了许多疾病，目前临床正在使用旨在抑制功能核糖核苷酸还原酶的抗菌和抗癌药物。然而，目前尚不清楚使这些酶失活的药物是如何起作用的。Gerfen博士的工作将使我们更好地了解核糖核苷酸还原酶的基本机制。

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.