Molecular Targets in Peptidoglycan Synthesis

肽聚糖合成中的分子靶标

• 批准号: 8787747
• 负责人: Christopher Davies
• 金额: $ 33.6万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-02-01 至 2016-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8787747
• 关键词: Active Sites; Acylation; Address; Alanine; Amidohydrolases; Amino Acids; Antibiotic Resistance; Antibiotics; Autolysin; Biochemical; Biological Process; C-terminal; Catalytic Domain; Cefixime; Ceftriaxone; Cell Wall; Cell division; Centers for Disease Control and Prevention (U.S.); Cephalosporin Resistance; Cephalosporins; Clinical; Complex; Data; Development; Dose; Drug Targeting; Enzymes; Exhibits; Fluoroquinolones; Goals; Gonorrhea; Infection; Investigation; Kinetics; Lactams; Light; Lytic; Mediating; Metabolism; Methods; Molecular; Molecular Target; Monobactams; Mutation; N-terminal; Neisseria gonorrhoeae; Organism; Penicillin Binding Protein 2; Penicillin Resistance; Penicillin-Binding Proteins; Penicillins; Peptides; Peptidoglycan; Peptidyltransferase; Positioning Attribute; Predisposition; Protein Dynamics; Proteins; Public Health; Relaxation; Reporting; Resistance; Role; Series; Sexually Transmitted Diseases; Specificity; Staging; Structural Protein; Structure; Substrate Specificity; Tertiary Protein Structure; Testing; Therapeutic; Treatment Failure; Variant; Withdrawal; X-Ray Crystallography; amidase; antimicrobial; base; crosslink; drug discovery; enzyme activity; inhibitor/antagonist; mutant; novel; protein structure; research study; resistant strain

DESCRIPTION (provided by applicant): Neisseria gonorrhoeae is the causative agent for the sexually transmitted disease gonorrhea and was responsible for over 350,000 infections in the U.S. in 2007. The steady and inexorable increase of resistance in this organism toward multiple classes of antibiotics has severely limited treatment options for gonococcal infections and, after the recent withdrawal of fluoroquinolones, the expanded-spectrum cephalosporin ceftriaxone is now the only single-dose treatment recommended by the CDC in the U.S. Unfortunately, new strains of N. gonorrhoeae have emerged that exhibit resistance to cefixime and ceftriaxone, and treatment failures are now being reported. This precarious position endangers public health and demands a better understanding of antibiotic resistance at the molecular level, as well as strategies to develop new antimicrobials directed against N. gonorrhoeae. This renewal application will address this need by investigating two enzymes of N. gonorrhoeae involved in peptidoglycan synthesis. One is penicillin-binding protein 2 (PBP 2), a transpeptidase that forms peptide cross-links during the latter stages of cell wall synthesis, and the clinical target for β-lactam antibiotics directed against this organism. Cephalosporin-resistant strains of N. gonorrhoeae harbor mutations in PBP 2 and a key goal is to determine the structural mechanisms that lower reactivity of PBP 2 with these antibiotics. We will also apply NMR relaxation methods to test the hypothesis that the molecular mechanism governing penicillin and cephalosporin resistance mediated by PBP 2 involves dynamic states of the protein. In recognition that other enzymes involved in peptidoglycan metabolism are potential targets for antimicrobials, we will also investigate N-acetylmuramyl-L-alanine amidase (AmiC), an autolysin that is required for proper cell division of N. gonorrhoeae. We have discovered that this enzyme exhibits autolytic activity in its N-terminal domain in addition to its known amidase activity in the C-terminal domain and therefore is a bifunctional autolysin. To understand the functional role of AmiC in peptidoglycan breakdown, but also to pave the way for drug discovery against its two active sites, we will obtain essential structural and biochemical information for AmiC.

描述（适用提供）：淋病奈瑟氏菌是性传播疾病淋病的灾难性药物，2007年在美国负责350,000多种感染。这种有机体对多种类别的抗生素的抗药性稳定且不可延缓的耐药性增加了，该抗生素具有严格的限制治疗方法，以促进果肉的癌症，并在最近的gonococcal Infortions and conquo​​ccal Infoription and，此后，此后，此后，此后，此后，此后，此后，之后，此后，之后，后来又是抗生素的抗生素。不幸的是，疾病预防控制中心（CDC）推荐的唯一的单剂量治疗已扩大，不幸的是，酸性链球菌的新菌株已经出现了对头孢菌症和头孢曲松的耐药性，现在报告了治疗失败。这种不稳定的立场危害了公共卫生，并要求更好地了解分子水平上的抗生素耐药性，以及开发针对Gonorrhoeae的新抗菌剂的策略。应用将通过研究参与肽聚糖合成的两种淋病猪笼草的酶来满足这一需求。一种是青霉素结合蛋白2（PBP 2），一种转肽酶，在细胞壁合成的后期形成肽交联，以及针对这种生物体的β-内酰胺抗生素的临床靶标。 PBP 2中淋病猪笼草ho骨突变的头孢菌素抗性菌株，关键目标是确定降低PBP 2对这些抗生素的反应性的结构机制。我们还将采用NMR弛豫方法来检验以下假设：PBP 2介导的青霉素和头孢菌素耐药的分子机制涉及蛋白质的动态状态。为了认识到涉及辣椒糖代谢的其他酶是抗菌剂的潜在靶标，我们还将研究N. gonorrhoeae的适当细胞分裂所必需的自身蛋白酶N-乙酰咪基氨基氨基氨基氨基氨基胺（AMIC）。我们已经发现，该酶在其N末端结构域中表现出自溶活性，此外其在C末端结构域中已知的胺化酶活性，因此是双功能自动蛋白。为了了解AMIC在PepperyDoglycan崩溃中的功能作用，同时也为与其两个活跃部位的药物发现铺平了道路，我们将获得友善的基本结构和生化信息。