Molecular mechanism of cephalosporin resistance of N. gonorrhoeae conferred by mutated PBP2

PBP2突变导致淋病奈瑟菌头孢菌素耐药的分子机制

• 批准号: 10589915
• 负责人: Christopher Davies
• 金额: $ 69.76万
• 依托单位: UNIVERSITY OF SOUTH ALABAMA
• 依托单位国家: 美国
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-03-10 至 2027-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10589915
• 关键词: Active Sites; Acylation; Alleles; Antibiotic Resistance; Antibiotics; Arthritis; Behavior; Binding; Biological Process; Cefixime; Ceftriaxone; Cell Wall; Cephalosporin Resistance; Cephalosporins; Complex; Contracts; Deuterium; Development; Female; Goals; Gonorrhea; Growth; HIV; Hydrogen; Impairment; Individual; Infection; Infertility; Investigation; Molecular; Molecular Conformation; Morphology; Movement; Mutate; Mutation; Neisseria gonorrhoeae; Organism; Pelvic Inflammatory Disease; Penicillin Binding Protein 2; Peptides; Peptidoglycan; Peptidyltransferase; Predisposition; Process; Protein Dynamics; Proteins; Public Health; Reaction; Relaxation; Resistance; Resolution; Risk; Role; Serine; Sexually Transmitted Agents; Sexually Transmitted Diseases; Side; Structure; Translating; Variant; X-Ray Crystallography; antimicrobial; beta-Lactams; design; experimental study; fitness; loss of function; molecular dynamics; mosaic; mutant; preservation; resistance mechanism; resistance mutation; resistant strain; sex; transmission process

Project Summary Neisseria gonorrhoeae, the causative agent for the sexually transmitted infection gonorrhea, is responsible for over 800,000 infections annually in the U.S. and 78 million cases worldwide. Untreated or untreatable infections can lead to infertility, pelvic inflammatory disease (PID) in females, gonococcal arthritis in both sexes, and an increased risk of both contracting and transmitting HIV. Over the past several decades, the inexorable increase of resistance in this organism toward multiple classes of antibiotics has severely limited treatment options for gonococcal infections. Most alarmingly, resistance against the extended-spectrum cephalosporin (ESC) ceftriaxone poses a serious threat to public health. This situation requires an understanding of antibiotic resistance at the molecular level in order to enable design of new antimicrobials. ESC resistance of N. gonorrhoeae is conferred by mutated forms of penicillin-binding protein 2 (PBP2). In this application, we propose to elucidate the molecular mechanism of resistance, with the overarching hypothesis that mutations in PBP2 restrict the molecular dynamics of the protein. It builds upon our recent understanding of the interactions made by wild-type PBP2 when bound by ESCs and how conformational changes associated with binding and acylation appear restricted in PBP2 derived from ESCR strains. The investigation comprises three aims: Specific Aim 1 is a structure-function analysis of wild-type PBP2 to investigate the importance of specific interactions formed when PBP2 is bound and acylated by cephalosporins. In Specific Aim 2, we will elucidate how key mutations present in PBP2 from ESCR strains of N. gonorrhoeae reduce inactivation by cephalosporins while retaining sufficient biological function to support growth of the organism. Finally, Specific Aim 3 will examine the behavior of PBP2 variants in solution to determine whether mutations hinder protein dynamics. By revealing the molecular mechanisms of how mutations in PBP2 overcome the lethal action of β-lactams, these investigations will enable new strategies for the development of replacement anti-gonococcal agents.

项目概要 淋病奈瑟菌是性传播感染淋病的病原体， 每年在美国造成超过 80 万例感染，在全世界造成 7,800 万例感染。未经处理或 无法治疗的感染可能导致不孕、女性盆腔炎 (PID)、淋菌性关节炎 无论男女，感染和传播艾滋病毒的风险都会增加。在过去的几十年里， 这种生物体对多种抗生素的耐药性不可避免地增加，这严重限制了 淋球菌感染的治疗选择。最令人担忧的是，对扩展频谱的抵制 头孢菌素（ESC）头孢曲松对公众健康构成严重威胁。这种情况需要一个 在分子水平上了解抗生素耐药性，以便能够设计新的抗菌药物。 淋病奈瑟菌的 ESC 抗性是由青霉素结合蛋白 2 (PBP2) 的突变形式赋予的。 在此应用中，我们建议阐明耐药性的分子机制，其总体目标是 假设 PBP2 的突变限制了蛋白质的分子动力学。它建立在我们最近的 了解野生型 PBP2 在与 ESC 结合时产生的相互作用以及构象如何 与结合和酰化相关的变化似乎在源自 ESCR 菌株的 PBP2 中受到限制。这 研究包括三个目标： 具体目标 1 是对野生型 PBP2 进行结构功能分析，以 研究当 PBP2 结合并酰化时形成的特定相互作用的重要性 头孢菌素类。在具体目标 2 中，我们将阐明 ESCR 菌株的 PBP2 中如何存在关键突变 淋病奈瑟菌减少头孢菌素的灭活，同时保留足够的生物功能以支持 有机体的生长。最后，具体目标 3 将检查 PBP2 变体在解决方案中的行为 确定突变是否阻碍蛋白质动力学。通过揭示如何的分子机制 PBP2 的突变克服了 β-内酰胺的致命作用，这些研究将为 替代性抗淋球菌药物的开发。