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Determination of the Biological Roles and Chemical Mechanisms of the Glutamate Ra

谷氨酸 Ra 的生物学作用和化学机制的测定

基本信息

批准号：
7882479
负责人：
Michael Ashley Spies
金额：
$ 23.54万
依托单位：
UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-07-06 至 2012-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Studies proposed in this R21 application address the urgent need to develop new classes of antibiotics against emerging infectious agents, as well as pathogenic bacteria with the potential to be used as bio-weapons. The long-term goal of the work proposed in this application is to develop a new class of inhibitors against glutamate racemases, which catalyze the stereo-inversion of L- to D-glutamate, an important metabolite for cell wall biosynthesis. Glutamate racemases are essential in several bacteria, but not found in mammals, and are thus predicted to be excellent antibiotic targets. Notably, at least three pharmaceutical companies are currently developing glutamate racemase inhibitors as potential antimicrobial drugs, thereby supporting the potential importance of the glutamate racemases as antimicrobial targets. However, our strategy for inhibitor design is entirely different than these companies, and is based on the transition state structure of glutamate racemase, which we predict will bind to the enzyme with higher affinity than do drugs based on the ground state enzyme-substrate complexes. In this R21 application, we propose exploratory studies towards the goals of (i) characterizing the importance and properties of the two Bacillus anthracis glutamate racemases, RacE1 and RacE2, in vitro and in vivo, and, (ii) generating models of the transition state structures of the reactions catalyzed by both enzymes. This highly interdisciplinary application consolidates considerable expertise in bioorganic and computational chemistry, biochemistry, and bacterial pathogenesis. The Specific Aims are: Specific Aim 1. To characterize the importance and roles of racE1 and racE2. Specific Aim 2. To characterize the transition states of RacE1- and RacE2-catalyzed racemization. The anticipated outcomes of these specific aims will be validation of glutamate racemase as a drug-target in B. anthracis, and the generation of transition state models for both RacE1 and RacE2. From these models, we will identify small molecule transition state analogs that will be screened for inhibitory activities against RacE1 and/or RacE2 enzyme activities. The results from these studies will provide the experimental and conceptual framework for future work to optimize small molecule "leads" into ultra-specific, reaction-based inhibitors with antimicrobial activity. PUBLIC HEALTH RELEVANCE: This application addressed an existing and urgent need to develop new classes of antibiotics against emerging infectious agents, as well as those agents that may potentially be used as bio-weapons. Completion of these studies will result in a new class of inhibitors with potential antimicrobial activity against Bacillus anthracis, which causes anthrax. The methodologies developed by work supported by this grant will also be potentially applicable to the development of antibiotics against other biomedically important pathogenic bacteria.

描述(由申请人提供)：本R21申请中提出的研究针对迫切需要开发新类别的抗生素，以对抗新出现的感染性病原体，以及有可能用作生物武器的病原菌。本申请中提出的工作的长期目标是开发一类新型的谷氨酸外消旋酶抑制剂，用于催化L立体转化为D-谷氨酸，D-谷氨酸是细胞壁生物合成的重要代谢物。谷氨酸消旋酶在几种细菌中是必需的，但在哺乳动物中没有发现，因此被预测为极好的抗生素靶标。值得注意的是，目前至少有三家制药公司正在开发谷氨酸外消旋酶抑制剂作为潜在的抗菌药物，从而支持谷氨酸外消旋酶作为抗菌靶标的潜在重要性。然而，我们的抑制剂设计策略与这些公司完全不同，是基于谷氨酸外消旋酶的过渡态结构，我们预测它将以比基于基态酶-底物复合物的药物更高的亲和力结合到酶上。在R21的应用中，我们提出了探索性研究的目标，目的是(I)表征两种炭疽芽孢杆菌谷氨酸消旋酶racE1和racE2在体内外的重要性和性质，以及(Ii)建立这两种酶催化的反应的过渡态结构的模型。这一高度跨学科的应用整合了生物有机和计算化学、生物化学和细菌发病机制方面的大量专业知识。具体目标是：具体目标1.确定racE1和racE2的重要性和作用。具体目的2.表征racE_1和racE_2催化的外消旋反应的过渡态。这些特定目标的预期结果将是验证谷氨酸消旋酶作为炭疽杆菌药物靶标的有效性，以及为racE1和racE2生成过渡态模型。从这些模型中，我们将识别小分子过渡态类似物，这些小分子过渡态类似物将被筛选出对racE1和/或racE2酶活性的抑制活性。这些研究的结果将为未来的工作提供实验和概念框架，以优化小分子“先导”，使其成为具有抗菌活性的超特异性、基于反应的抑制剂。公共卫生相关性：这项申请解决了现有的迫切需要开发新的抗生素类别，以对抗新出现的感染性病原体，以及那些可能被用作生物武器的病原体。这些研究的完成将导致一类新的抑制剂，对引起炭疽的炭疽芽孢杆菌具有潜在的抗菌活性。由这笔赠款支持的工作开发的方法也可能适用于开发针对其他生物医学重要病原菌的抗生素。