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

• 批准号: 7740323
• 负责人: Michael Ashley Spies
• 金额: $ 19.81万
• 依托单位: UNIVERSITY OF ILLINOIS AT URBANA-CHAMPAIGN
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-06 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7740323
• 关键词: Address; Affinity; Anabolism; Anthrax disease; Antibiotics; Bacillus anthracis; Bacteria; Binding; Biochemistry; Biological; Cell Wall; Chemicals; D Glutamate; Development; Drug Delivery Systems; Enzymes; Future; Generations; Glutamate racemase; Glutamates; Goals; Grant; In Vitro; Infectious Agent; Knowledge; Mammals; Methodology; Modeling; Outcome; Pathogenesis; Peptidoglycan; Pharmaceutical Preparations; Pharmacologic Substance; Property; Reaction; Research; Role; Screening procedure; Source; Structure; Validation; Work; analog; antimicrobial; antimicrobial drug; base; computational chemistry; design; enzyme activity; enzyme substrate complex; in vivo; inhibitor/antagonist; pathogen; pathogenic bacteria; public health relevance; racemization; small molecule; weapons

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 申请中提出的研究解决了开发新型抗生素的迫切需要，以对抗新出现的传染源以及可能用作生物武器的病原菌。本申请提出的工作的长期目标是开发一类新型谷氨酸消旋酶抑制剂，其催化L-谷氨酸立体转化为D-谷氨酸，这是细胞壁生物合成的重要代谢物。谷氨酸消旋酶在多种细菌中是必需的，但在哺乳动物中未发现，因此预计是极好的抗生素靶点。值得注意的是，至少三个制药公司目前正在开发谷氨酸消旋酶抑制剂作为潜在的抗菌药物，从而支持谷氨酸消旋酶作为抗菌靶点的潜在重要性。然而，我们的抑制剂设计策略与这些公司完全不同，并且基于谷氨酸消旋酶的过渡态结构，我们预测与基于基态酶-底物复合物的药物相比，它将以更高的亲和力与酶结合。在此 R21 应用中，我们提出探索性研究，目标是 (i) 在体外和体内表征两种炭疽杆菌谷氨酸消旋酶 RacE1 和 RacE2 的重要性和特性，以及 (ii) 生成过渡态模型两种酶催化的反应的结构。这种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. 描述 racE1 和 racE2 的重要性和作用。具体目标 2. 表征 RacE1 和 RacE2 催化的外消旋化的过渡态。 这些具体目标的预期结果将是验证谷氨酸消旋酶作为炭疽芽孢杆菌的药物靶标，以及生成 RacE1 和 RacE2 的过渡态模型。从这些模型中，我们将鉴定小分子过渡态类似物，并筛选其对 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。公共健康相关性：本申请解决了开发针对新出现的传染性病原体以及可能用作生物武器的新型抗生素的现有迫切需求。这些研究的完成将产生一类新的抑制剂，对引起炭疽的炭疽杆菌具有潜在的抗菌活性。这笔资助支持的工作开发的方法也将有可能适用于针对其他生物医学上重要的病原菌的抗生素的开发。