Penicillin-Binding Proteins, Mechanism and Inhibition

青霉素结合蛋白、机制和抑制

• 批准号: 7026518
• 负责人: Shahriar Mobashery
• 金额: $ 27.1万
• 依托单位: UNIVERSITY OF NOTRE DAME
• 依托单位国家: 美国
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2009-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7026518
• 关键词: Escherichia coli; Staphylococcus aureus; bacterial proteins; beta lactam antibiotic; binding proteins; carboxypeptidase; cell wall; cephalosporins; crystallization; drug design /synthesis /production; drug discovery /isolation; enzyme activity; enzyme inhibitors; glycosidases; high performance liquid chromatography; microorganism metabolism; molecular assembly /self assembly; molecular cloning; penicillins; pharmacokinetics; protein structure function; transpeptidation

DESCRIPTION (provided by applicant): Cell wall is indispensable for survival of bacteria. The building blocks of the bacterial peptidoglycan, the major constituent of cell wall, are assembled within the cytoplasm, then they are transported to the surface of the cytoplasmic membrane. The final steps of cell wall assembly take place on the cytoplasmic membrane by a set of enzymes referred to as penicillin-binding proteins (PBPs). The naming of these enzymes stems from the determination that they serve as the targets for beta-lactam antibiotics (penicillins, cephalosporins, etc.). Three important biochemical activities for PBPs are the transglycosylase, DD-transpeptidase and DD-carboxypeptidase activities. Investigations of these enzymic activities are disclosed in this grant application. Three Specific Aims are offered. Specific Aim 1 is to study the reactions of both the bifunctional and monofunctional DD-transpeptidases. Specific Aim 2 describes the detailed studies of the reactions of two DD-carboxypeptidases. Synthetic substrates that closely mimic the polymeric substrates for these enzymes have been developed in the Mobashery lab for detailed study of the microscopic steps of the reactions of these enzymes. Furthermore, computational studies are outlined to elucidate the details of the reactions of these enzymes. Specific Aim 3 will be the continuation of the efforts in development of non-beta-lactam inhibitors for PBPs as potential antibiotics. Currently only beta-lactams are used clinically in inhibition of these enzymes, but beta-lactams may be facing obsolescence in the near future because of widespread resistance to them. Three classes of non-beta-lactam leads for inhibition of PBPs have been identified and will be the subjects of study by generation of focused libraries of related compounds in quest for the desired non- beta-lactam antibiotics that target PBPs for inhibition. It is expected that the outcome of these studies will shed definitive light on the biochemical mechanisms of PBPs and pave the way for discoveries of novel inhibitors as potential future antibiotics.

描述（由申请人提供）： 细胞壁对于细菌的生存是不可缺少的。细菌肽聚糖（细胞壁的主要成分）的组成部分在细胞质内组装，然后被转运到细胞质膜的表面。细胞壁组装的最后步骤是通过一组称为青霉素结合蛋白 (PBP) 的酶在细胞质膜上进行的。这些酶的命名源于它们作为β-内酰胺抗生素（青霉素、头孢菌素等）的靶标的确定。 PBP 的三个重要生化活性是转糖基酶、DD-转肽酶和 DD-羧肽酶活性。本拨款申请中公开了对这些酶活性的研究。提出了三个具体目标。具体目标 1 是研究双功能和单功能 DD 转肽酶的反应。具体目标 2 描述了两种 DD-羧肽酶反应的详细研究。 Mobashery 实验室开发了与这些酶的聚合底物极为相似的合成底物，用于详细研究这些酶反应的微观步骤。此外，还概述了计算研究来阐明这些酶的反应细节。具体目标 3 将继续努力开发 PBP 的非 β-内酰胺抑制剂作为潜在的抗生素。目前临床上仅使用β-内酰胺来抑制这些酶，但由于对它们的广泛耐药性，β-内酰胺可能在不久的将来面临淘汰。已鉴定出三类用于抑制 PBP 的非 β-内酰胺先导化合物，并将通过生成相关化合物的重点文库作为研究对象，以寻求靶向 PBP 进行抑制的所需非 β-内酰胺抗生素。预计这些研究的结果将明确阐明 PBP 的生化机制，并为发现作为未来潜在抗生素的新型抑制剂铺平道路。