Mechanistic studies and inhibition strategies for antibiotic resistance

抗生素耐药性的机制研究和抑制策略

• 批准号: 7658125
• 负责人: FOCCO VAN DEN AKKER
• 金额: $ 26.52万
• 依托单位: CASE WESTERN RESERVE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-07-15 至 2011-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7658125
• 关键词: Active Sites; Adopted; Affect; Amides; Amines; Antibiotic Resistance; Antibiotics; Bacterial Infections; Binding; Carbapenems; Ceftazidime; Cephalosporins; Charge; Complex; Crystallography; Cyclization; Disease Outbreaks; Entropy; Goals; Health; Health Care Costs; Human; Hydrolysis; Infection; Klebsiella pneumonia bacterium; Knowledge; Lactamase; Lactams; Lead; Length; Mediating; Molecular; Monobactams; New York; Penicillins; Phenotype; Point Mutation; Reaction; Research Personnel; Resistance; Resistance development; Resort; Roentgen Rays; Side; Structure; Tazobactam; Testing; Variant; Virus Diseases; analog; base; beta-Lactamase; beta-lactamase PSE-2; carbapenemase; cost; deacylation; design; flexibility; flu; improved; inhibitor/antagonist; innovation; insight; methyl group; mutant; novel; novel therapeutic intervention; programs; pyridine; unsaturated bonds; uptake

DESCRIPTION (provided by applicant): Bacterial infections pose serious threats to human health. Furthermore, viral infections such as the flu are frequently accompanied by bacterial infections which is often a deadly combination. Due to the development of resistance, the options for treating infections have dwindled substantially. This resistance is in large part due to the bacterial expression of beta-lactamases that degrade beta-lactam antibiotics including penicillins, cephalosporins, and the "last resort" carbapenem antibiotics. An alternative approach for treating p-lactam resistant gram-negative infections is co-administering a p-lactamase inhibitor in addition to penicillin-like antibiotics. Regrettably, p-lactamases have also evolved an inhibitor-resistant phenotype able to overcome this treatment option. The p-lactamase variants that hydrolyze these inhibitors are called inhibitor resistant [3-lactamases, those that hydrolyze cephalosporins are called extended-spectrum p-lactamases (ESBLs), and those that hydrolyze carbapenems are known as carbapenemases. The overarching goals of this proposal are to understand the structural basis of the phenotypes of ESBL-, carbapenemase-, and inhibitor resistant p-lactamases, and to develop novel inhibition strategies. Our structure-function studies involve a novel synergy between X-ray and Raman crystallography and this innovative inter-disciplinary approach allows us to identify and track reaction intermediates inside crystals prior to X-ray analysis and provides a unique advantage to accomplish our Aims. Aim 1: To further improve our novel designed beta-lactamase inhibitor SA2-13 by modifying the overall charge and carboxyl linker to improve uptake and trans-enamine stabilization. Aim 2: To test the hypothesis that the changes in or near D179 which are present in ESBL's SHV-6, -8, and -24 have evolved to hydrolyze ceftazidime by shifting the omega loop thereby extending the active site to accommodate ceftazidime. Aim 3: To test the hypothesis that class A carbapenemases such as KPC-2 have adopted a shallower active site and flexible catalytic 870 side chain to efficiently hydrolyze carbapenems. Aim 4: To test the hypothesis that inhibitors that either can carry out bi-cyclization (such as LN1-255) or fra/is-enamine inhibitors (SA2-13) are capable of forming stable inhibitory complexes with inhibitor-resistant class A and inhibitor-insensitive class D p-lactamases. The impact of beta-lactamase mediated antibiotic resistance on human health is enormous, costing billions of dollars in health care costs. Detailed understanding is needed and our targeted structural knowledge will provide for molecular insights into cases such as the recent outbreaks of KPC mediated carbapenem-resistant K. pneumoniae in New York. These resistance insights will lead to new therapeutic approaches and our goal is to study and develop new broad-spectrum beta-lactamase inhibitors.

描述（申请人提供）：细菌感染对人类健康构成严重威胁。此外，流感等病毒感染经常伴有细菌感染，这往往是致命的组合。由于耐药性的发展，治疗感染的选择已大大减少。这种耐药性在很大程度上是由于细菌表达β-内酰胺酶，这些酶会降解β-内酰胺类抗生素，包括青霉素、头孢菌素和“最后的手段”碳青霉烯类抗生素。治疗β-内酰胺耐药性革兰氏阴性菌感染的另一种方法是除了青霉素类抗生素外，联合施用β-内酰胺酶抑制剂。遗憾的是，β-内酰胺酶也进化出了一种抑制剂抗性表型，能够克服这种治疗选择。水解这些抑制剂的β-内酰胺酶变体称为抑制剂抗性[3-内酰胺酶，水解头孢菌素的β-内酰胺酶称为超广谱β-内酰胺酶(ESBL)，水解碳青霉烯类的酶称为碳青霉烯酶。该提案的总体目标是了解 ESBL、碳青霉烯酶和抑制剂耐药性 β-内酰胺酶表型的结构基础，并开发新的抑制策略。我们的结构功能研究涉及 X 射线和拉曼晶体学之间的新颖协同作用，这种创新的跨学科方法使我们能够在 X 射线分析之前识别和跟踪晶体内部的反应中间体，并为实现我们的目标提供独特的优势。目标 1：通过修改总电荷和羧基连接体来进一步改进我们新型设计的 β-内酰胺酶抑制剂 SA2-13，以提高摄取和反式烯胺稳定性。目标 2：检验以下假设：ESBL 的 SHV-6、-8 和 -24 中存在的 D179 中或附近的变化已进化为通过移动 omega 环来水解头孢他啶，从而扩展活性位点以容纳头孢他啶。目标 3：检验 A 类碳青霉烯酶（例如 KPC-2）采用较浅的活性位点和灵活的催化 870 侧链来有效水解碳青霉烯类的假设。目标 4：检验以下假设：能够进行双环化的抑制剂（例如 LN1-255）或 fra/is-enamine 抑制剂（SA2-13）能够与 A 类抑制剂形成稳定的抑制复合物，并且对抑制剂不敏感的 D 类 p-内酰胺酶。 β-内酰胺酶介导的抗生素耐药性对人类健康的影响是巨大的，造成数十亿美元的医疗保健费用。需要详细的了解，我们有针对性的结构知识将为诸如最近在纽约爆发的 KPC 介导的耐碳青霉烯类肺炎克雷伯菌等病例提供分子见解。这些耐药性见解将带来新的治疗方法，我们的目标是研究和开发新的广谱 β-内酰胺酶抑制剂。