Bulgecin Template for Potentiation of beta-Lactam Antibiotics

用于增强 β-内酰胺抗生素的 Bulgecin 模板

• 批准号: 10438764
• 负责人: Shahriar Mobashery
• 金额: $ 62.9万
• 依托单位: UNIVERSITY OF NOTRE DAME
• 依托单位国家: 美国
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-07-01 至 2025-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10438764
• 关键词: Address; Anti-Bacterial Agents; Antibiotics; Applications Grants; Aspartate; Aspartic Acid; Attention; Bacteria; Binding; Ceftazidime; Chemosensitization; Clinical; Complex; Computer Analysis; Cytolysis; Event; Exhibits; Failure; Fluorescence Microscopy; Gene Cluster; Genes; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Host resistance; In Vitro; Infection; Lead; Lytic; Meropenem; Methodology; Methods; Microbiology; Monobactams; Natural Products; Organism; Pathway interactions; Penetration; Phase; Preparation; Process; Production; Property; Pseudomonas aeruginosa; Pseudomonas aeruginosa infection; Reaction; Reporting; Research; Resistance; Rodent Model; Roentgen Rays; Scanning Electron Microscopy; Series; Serine; Site; Structure; Work; analog; bactericide; beta-Lactams; chemical synthesis; experimental study; fighting; human pathogen; in vivo; lead optimization; novel; novel strategies; pathogen; periplasm; resistance mechanism

Project Summary/Abstract Gram-negative bacteria have become broadly resistant to known classes of antibiotics. Treatment of infections by these pathogens has become increasingly challenging and efforts in the past two decades in discoveries of new classes of antibacterial agents have failed. In this grant application, we have turned our attention to bulgecins, a group of three natural products (bulgecins A, B and C) discovered in the 1980s, which potentiate the activities of b-lactam antibiotics to Gram-negative bacteria. The three natural products were prepared by total synthesis and we documented the potentiation activity in microbiological experiments. Furthermore, we documented by both fluorescence microscopy and by scanning-electron microscopy that the combination of bulgecin A and a b-lactam antibiotic (ceftazidime or meropenem) cause bulges in the bacterial envelope, which are points of structural instability that burst and lead to bactericidal effect. In addition, we documented that merely two lytic transglycosylases out of 11 in Pseudomonas aeruginosa—Slt and MltD (with ceftazidime) and Slt and MltG (with meropenem)—are the targets of bulgecin A. We also report the X-ray structure for the complex of Slt with bulgecin A. We disclose the next phase of this research in two Specific Aims. Specific Aim 1 addresses our planned analysis of the bulgecin-biosynthetic cluster, which we discovered recently. The eight-gene cluster converts L-serine and L-aspartic acid to bulgecinine, a key structural component of bulgecins, and then in turn, to bulgecins A, B and C. We propose to study these genes both for their enzymological reactions and for their structures. A proposal is outlined to prepare the high-value bulgecinine using a host bacterium as a “one-pot” reaction vessel. We already have reported a chemical synthesis for bulgecinine and a second (shorter) synthetic approach is also proposed. A detailed plan is outlined in Specific Aim 2 to optimize the bulgecin template. The process takes advantage of our X-ray structure for the complex of Slt and bulgecin A in a computational analysis to identify analogs that will bind more potently to lytic transglycosynases and achieve penetration into Gram-negatives more avidly. The proposed targets will be synthesized and fully analyzed in a series of both in vitro and in vivo experiments in identification of a suitable combination of a bulgecin analog with a b-lactam antibiotic in fighting Gram-negative bacterial infections.

项目摘要/摘要 革兰氏阴性细菌已经对已知类别的抗生素具有广泛的抗性。感染的治疗 在过去的二十年中，这些病原体已变得越来越具有挑战性和努力 新的抗菌剂失败了。在此赠款申请中，我们将注意力转向 Bulgecins是1980年代发现的三种天然产品（Bulgecins A，B和C） B-内酰胺抗生素对革兰氏阴性细菌的活性。这三种天然产品由 总合成，我们记录了微生物学实验中的增强活性。此外，我们 通过荧光显微镜和扫描电子显微镜记录 Bulgecin A和B-内酰胺抗生素（头孢济或Meropenem）会引起细菌包膜的凸起 是结构不稳定的点，会破裂并导致细菌作用。此外，我们记录了 铜绿假单胞菌中的11个中只有两个裂解的糖基酶-SLT和MLTD（带有头孢济）和 SLT和MLTG（带有Meropenem） - 是Bulgecin A的目标。我们还报告了该X射线结构的X射线结构 SLT与Bulgecin A的复合物A以两个特定的目的披露了这项研究的下一阶段。具体目标 1解决了我们最近发现的Bulgecin-Biosynthetic群集的计划分析。 八基因簇将L丝氨酸和L-天冬氨酸转换为Bulgecinine，这是一个关键的结构成分 Bulgecins，然后是Bulgecins A，B和C。我们建议研究这些基因 酶促反应及其结构。提出了一项提案，以准备高价值bulgecinine 使用宿主细菌作为“一锅”反应容器。我们已经报道了一种化学合成 还提出了Bulgecinine和第二种（退缩）合成方法。特定的详细计划概述了 目标2以优化Bulgecin模板。该过程利用了我们的X射线结构 计算分析中的SLT和Bulgecin A，以识别将更可能与裂解结合的类似物 跨糖合酶并更加狂热地渗透到革兰氏阴性症中。拟议的目标将是 在一系列体外和体内实验中综合和完全分析，以鉴定合适的 Bulgecin类似物与B-内酰胺抗生素的结合在抗革兰氏阴性细菌感染中。