Mechanism of Orotidine-5'-Monophosphate Decarboxylase

Orotidine-5-单磷酸脱羧酶的机制

基本信息

批准号：
7229132
负责人：
Weiming Wu
金额：
$ 18万
依托单位：
SAN FRANCISCO STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2007
资助国家：
美国
起止时间：
2007-01-01 至 2010-12-31
项目状态：
已结题

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

Orotidine 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的构建基块的生物合成至关重要 RNA，因此ODCase的抑制剂可能具有显着的治疗价值。尽管最近很重要进步，尚不理解哪些因素在与ODCASE结合和催化的结合和催化中很重要。这缺乏这样的知识是一个关键的缺口，因为理解这些因素对于该酶有效抑制剂的设计。我们的远程目标是了解催化 ODCASE的机制并根据机制设计有效的ODCase抑制剂。这该应用的目的是追求该目标的一步，是结构性的确定底物的成分及其对结合和催化很重要的类似物。中央该应用的假设是zwitterionic含量（由质子亲和力确定）是最大的确定模型和酶催化反应中脱羧速率的重要因素 odcase使用结合的紧密度和远程结合位点的结合能催化反应。该假设将通过追求以下两个具体目标来检验：1）确定Zwitterion中间体在模型中的作用和酶促脱羧的作用底物类似物，并识别底物的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）确定远程绑定位点的作用（核糖部分上的羟基）朝着结合和催化。拟议的研究是创新，因为它结合了模型和酶学研究以确定ZWITTERIOIC结构的作用在反应机制中，确定对结合和催化重要的因素。这因此，贡献是重要的，因为它将提供对酶使用方式的理解一般催化中的远程结合能以及有效和有效和设计的设计尤其是ODCASE的选择性抑制剂。与公共卫生有关：开发有效的ODCASE抑制剂是非常兴趣的，因为它是核酸生物合成机制的一部分。抑制这些基础的生物合成已在癌症化疗中被利用。许多其他嘧啶拮抗剂已被证明是用于抗肿瘤和抗病毒化学疗法