Cell-Wall Recycling and Nexus to Antibiotic Resistance

细胞壁回收及其与抗生素耐药性的关系

• 批准号: 10401291
• 负责人: Shahriar Mobashery
• 金额: $ 38.63万
• 依托单位: UNIVERSITY OF NOTRE DAME
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-05-01 至 2024-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10401291
• 关键词: Antibiotic Resistance; Antibiotics; Applications Grants; Bacteria; Biochemical Process; Carbapenems; Cell Wall; Cephalosporins; Clinical; Complex; Cytoplasm; Enterobacteriaceae; Enzymes; Event; Future; Genetic Transcription; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Growth; Host resistance; Individual; Interruption; Knowledge; Lead; Link; Lytic; Mission; Monobactams; Natural Products; Outcome; Penicillins; Physiological Processes; Process; Proteins; Pseudomonas aeruginosa; Reaction; Recycling; Resistance; Science; Structure; Study Subject; System; base; beta-Lactam Resistance; beta-Lactamase; beta-Lactams; cell injury; chemical reaction; expectation; human pathogen; novel strategies; pathogen; periplasm; repaired; resistance mechanism; response

Project Summary/Abstract Cell-wall recycling is a fundamental process in bacteria, whereby it allows for remodeling of the cell wall in the course of the normal growth and in response to antibiotics that inflict damage to the cell wall for their mechanisms of action. Enterobacteriaceae and Pseudomonas aeruginosa (subject of this grant application) sense damage inflicted to their cell wall by β-lactam antibiotics. The sensing event is linked to cell-wall recycling, which leads to the formation of cell-wall-based natural products known as muropeptides. Certain muropeptides are internalized to the cytoplasm, where they induce the bacterial response to the antibiotic (antibiotic-resistance mechanisms). This process has led to obsolescence of many of the β-lactam antibiotics against Gram-negative bacteria. My lab has studied this system for the past several years and what I disclose in this MIRA application is the path that the lab will chart in the immediate future. I propose to study the periplasmic complexes involving lytic transglycosylases (LTs), which turn over the cell wall for the purpose of recycling or in response to damage by antibiotics. My lab has documented that there are 11 known LTs in P. aeruginosa, whose individual reactions with the cell wall have been described by us. These enzymes are proposed to be involved in complexes with other proteins within the periplasm, whose identities are not known and represent a major gap in our knowledge of cell-wall processes. Whereas all the functions of LTs are not understood, one is repair of cell wall upon exposure of bacteria to β-lactam antibiotics. Muropeptides are the degradation products of cell-wall recycling, which are internalized to the cytoplasm for this purpose. As an offshoot of the recycling events, certain muropetides activate the AmpR transcriptional regulator in expression of the AmpC β-lactamase, the resistance determinant for β-lactam antibiotics. We will study the interactions of the key mutropeptides with the AmpR protein in elucidating the system. Furthermore, four additional cytoplasmic enzymes that have been identified in P. aeruginosa for the key events of the muropeptide recycling will be investigated for their chemical reactions, the details of the catalytic cycles and for their structures. I anticipate that the successful completion of this proposed science will not only lead to the elucidation of these important events regulating the cell wall, but also will identify opportunities for their interruption as a means to circumventing the elaborate mechanism of β-lactam resistance that Gram-negative bacteria have evolved. These complex events are poorly understood, and they will be studied in detail in my lab in the course of the proposed reseach.

项目摘要/摘要 细胞壁回收是细菌中的一个基本过程，从而可以重塑细胞壁 正常生长的过程和对抗生素的响应，这些抗生素会损害细胞壁 作用机理。肠杆菌科和铜绿假单胞菌（本赠款申请的主题） β-内酰胺抗生素对其细胞壁造成的感觉损害。灵敏度事件与细胞壁有关 回收，导致形成基于细胞壁的天然产物，称为杂肽。肯定 杂肽内部对细胞质内部化，它们在其中诱导细菌对抗生素的反应 （抗生素耐药机制）。这个过程导致许多β-内酰胺抗生素的过时 抗革兰氏阴性细菌。在过去的几年中，我的实验室研究了该系统，我透露了什么 在此MIRA应用程序中，实验室将在不久的将来绘制图表。我建议研究 涉及裂解乳糖基酶（LTS）的周质复合物，其翻转细胞壁是为了目的 回收或响应抗生素损伤。我的实验室记录了P中有11个已知LT。 我们描述了铜绿物，其与细胞壁的各个反应已被我们描述。这些酶是 提议参与周内与其他蛋白质的复合物，其身份尚不清楚 并代表我们对细胞壁过程的知识的主要差距。 LT的所有功能都不是 理解，一个是在细菌暴露于β-内酰胺抗生素的情况下修复细胞壁。杂肽是 为此目的，将细胞壁回收的降解产物内化为细胞质。作为 回收事件的分支，某些穆洛皮酯在表达中激活AMPR转录调节剂 AMPCβ-内酰胺酶，β-内酰胺抗生素的耐药性确定抑制剂。我们将研究 与AMPR蛋白阐明系统的关键毒素肽。此外，另外四个 在铜绿假单胞菌中已鉴定出的细胞质酶为鼠的关键事件 将研究回收的化学反应，催化周期的细节及其 结构。我预计该提出的科学的成功完成不仅会导致 阐明这些重要事件来调节细胞墙，但也将确定其机会 中断作为绕过β-内酰胺耐药性的精细机制的一种手段 细菌已经进化。这些复杂的事件的理解很少，它们将在我的 在拟议的提议过程中实验室。