Mechanism of Orotidine-5'-Monophosphate Decarboxylase

Orotidine-5-单磷酸脱羧酶的机制

基本信息

批准号：
7751324
负责人：
Weiming Wu
金额：
$ 18.49万
依托单位：
SAN FRANCISCO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

项目摘要

Orotidine 5'-monophosphate decarboxylase (ODCase) is a key enzyme in the de novo pyrimidine biosynthetic pathway. This pathway is essential for the biosynthesis of building blocks for both DNA and RNA, and thus inhibitors of ODCase could have significant therapeutic value. Despite recent significant advances, it is not understood what factors are important in binding to and catalysis by ODCase. The lack of such knowledge is a critical defecit because understanding these factors is essential to the design of potent inhibitors for this enzyme. Our long-range goal is to understand the catalytic mechanism of ODCase and to design potent inhibitors of ODCase based on the mechanism. The objective of this application, which is a step in pursuit of that goal, is the identification of structural components of the substrate and its analogs that are important for binding and catalysis. The central hypothesis of the application is that the zwitterionic content (determined by proton affinity) is the most important factor in determining the rate of decarboxylation in model and enzyme-catalyzed reactions as well as the tightness of binding and that binding energy from remote binding sites is utilized by ODCase to catalyze the reaction. The hypothesis will be tested by pursuing the following two specific aims: 1) Identify the role played by the zwitterionic intermediate in the model and enzymatic decarboxylation of substrate analogs and identify the structural components on the pyrimidine ring of the substrate and analogs that are important for binding and catalysis; and 2) Determine the role of remote binding sites (the hydroxy groups on the ribose moiety) toward binding and catalysis. The proposed research is innovative because it combines model and enzymatic studies to identify the role of zwitterioic structures in the reaction mechanism and to determine the factors important for binding and catalysis. This contribution is significant, therefore, because it will provide an understanding of how enzymes utilize remote binding energy in catalysis in general, and the mechanism as well as the design of potent and selective inhibitors of ODCase, in particular. Relevance to Public Health: It is of great interest to develop potent inhibitors of ODCase because it is part of the nucleic acid biosynthesis machinery. Inhibition of the biosynthesis of these building blocks has been exploited in cancer chemotherapy. Many other pyrimidine antagonists have been shown to be useful in antitumor and antiviral chemotherapy

乳清苷 5'-单磷酸脱羧酶 (ODCase) 是从头嘧啶的关键酶生物合成途径。该途径对于 DNA 和 DNA 构建模块的生物合成至关重要。 RNA 以及 ODCase 抑制剂可能具有重要的治疗价值。尽管最近发生了重大尽管取得了进展，但尚不清楚哪些因素对于 ODCase 的结合和催化是重要的。这缺乏这些知识是一个严重缺陷，因为了解这些因素对于设计该酶的有效抑制剂。我们的长期目标是了解催化 ODCase的作用机制，并根据该机制设计有效的ODCase抑制剂。这该应用程序的目标是实现该目标的一个步骤，是识别结构对结合和催化很重要的底物及其类似物的成分。中央该应用的假设是两性离子含量（由质子亲和力确定）是最大的决定模型和酶催化反应脱羧速率的重要因素以及结合的紧密度以及 ODCase 利用来自远程结合位点的结合能来催化反应。该假设将通过追求以下两个具体目标来检验：1）确定两性离子中间体在模型和酶促脱羧中所起的作用底物类似物并鉴定底物嘧啶环上的结构成分和对于结合和催化很重要的类似物； 2) 确定远程结合位点的作用（核糖部分上的羟基）用于结合和催化。拟议的研究是创新性在于它结合了模型和酶学研究来确定两性结构的作用反应机理并确定对结合和催化重要的因素。这因此，贡献是重要的，因为它将提供对酶如何利用的理解一般催化中的远程结合能，以及有效和有效的机制以及设计特别是ODCase的选择性抑制剂。与公共健康的相关性：开发 ODCase 的有效抑制剂引起了极大的兴趣，因为它核酸生物合成机器的一部分。抑制这些结构单元的生物合成已被用于癌症化疗。许多其他嘧啶拮抗剂已被证明具有可用于抗肿瘤和抗病毒化疗