Characterization of novel MurA inhibitors

新型 MurA 抑制剂的表征

• 批准号: 6959212
• 负责人: ERNST SCHONBRUNN
• 金额: $ 7.2万
• 依托单位: UNIVERSITY OF KANSAS LAWRENCE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-07-01 至 2007-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6959212
• 关键词: X ray crystallography; active sites; alkyltransferase; antibiotics; catalyst; chemical kinetics; drug design /synthesis /production; drug discovery /isolation; drug resistance; enzyme activity; enzyme inhibitors; enzyme structure; fluorescence spectrometry; pharmacokinetics

DESCRIPTION (provided by applicant): The ability of penicillin and other modern antibiotics to control infectious diseases has been steadily eroded by the emergence of multiple-antibiotic-resistant strains of bacteria. The CDC estimates that 90,000 Americans die from bacterial infections annually, with 70% of these infections involving antibiotic-resistant strains. Bacterial survival strictly depends on the functionality of the cytosolic enzyme MurA, which catalyzes the first committed step in the synthesis of the bacterial cell. It is the target of the naturally occurring, broad spectrum antibiotic fosfomycin. Fosfomycin, an epoxide, covalently attacks a critical cysteine-residue of MurA (Cys115). This residue-directed mode of action renders fosfomycin a relatively poor drug, because in pathogenic bacteria, such as Mycobacterium tuberculosis, Cys115 is replaced by an aspartate. In addition, an ever-increasing number of pathogenic bacteria have developed resistance to fosfomycin due to decreased transport of fosfomycin into the cell, and inactivation by a fosfomycin resistance protein (FosA). Thus, there is a critical need for the development of novel drugs targeting MurA by a different molecular mode of action. We have recently identified five new MurA inhibitors with unique scaffolds and IC50 values ranging from 2 mu M to 8 mu M by high-throughput screening (HTS) using a 50,000 compound library. The central goal of this proposal is to thoroughly evaluate the mode of action of these new lead structures on MurA. The specific aim, which integrates enzyme kinetics and protein crystallography, is to perform inhibition kinetics and determine the crystal structure of MurA bound with these inhibitors in order to resolve the structure-activity relationships in atomic detail. The long-term goal of this proposal is to provide a basis for the rational design of novel potent broad-spectrum antibacterial drugs that specifically target MurA.

描述（由申请人提供）：青霉素和其他现代抗生素控制感染性疾病的能力已因多种抗生素抗性细菌的菌株的出现而稳步侵蚀。疾病预防控制中心估计，每年有90,000名美国人死于细菌感染，其中70％的感染涉及抗生素抗性菌株。细菌的生存严格取决于胞质酶Mura的功能，该酶Mura催化了细菌细胞合成的第一步。它是天然存在的广谱抗生素fosfymycin的靶标。环氧化物Fosfomycin共价攻击MURA的关键半胱氨酸 - Cys115。这种残基指导的作用方式使Fosfomycin成为相对较差的药物，因为在致病性细菌（例如结核分枝杆菌）中，Cys115被天冬氨酸取代。此外，由于fosfomycin降低到细胞的运输，并被fosfymycin耐药性蛋白（FOSA）灭活，因此数量不断增加的致病细菌已经对fosfomycin产生了抗性。因此，迫切需要通过不同的分子作用方式开发针对Mura的新型药物。 我们最近使用50,000个化合物库通过高通量筛选（HTS）确定了五个新的MURA抑制剂，具有独特的脚手架和IC50值，范围从2 mu m至8 mu m。该提案的核心目标是彻底评估这些新的铅结构对Mura的作用方式。整合酶动力学和蛋白质晶体学的特定目的是执行抑制动力学并确定与这些抑制剂结合的Mura的晶体结构，以解决原子细节的结构活性关系。该提案的长期目标是为专门针对Mura的新型有效广谱抗菌药物的合理设计提供基础。