Discovery and characterization of new bacterial cell wall targets and inhibitors to treat resistant infections

项目摘要 对抗生素具有抗药性的细菌感染对人类健康构成了巨大且日益严重的威胁。有一个 迫切需要确定新的抗菌目标的特征，并开发能够发现和 这些靶标的抑制剂的表征。这里描述的研究侧重于理解晚期 细菌细胞周围的肽多聚糖细胞壁的组装步骤。细胞壁对于 细菌存活，使其成为抗生素的杰出靶点。事实上，一些最重要的抗生素 在历史上，β-内酰胺和糖肽针对的是肽聚糖组装的后期步骤。从历史上看， 催化这些后期步骤的酶由于其性质而极难研究 所需的底物，形成的产物，以及许多肽聚糖生物合成的事实 酶是多面体的膜蛋白，或者只有在与膜蛋白络合时才起作用。近期 我们实验室的技术创新推动了肽聚糖生物合成领域的发展 相当大，我们能够追求以前没有研究过的具有挑战性的目标。这个项目 有四个目标。目标1涉及进一步开发化学工具，以使机械和结构 细胞壁生物合成酶的研究。目标2侧重于理解Murj，即输出 肽聚糖前体Lipid II从细胞质到细胞表面，在那里聚合产生 多肽聚糖。目标3重点研究唯一一种普遍保守的肽聚糖FtsW的特性 细菌中的聚合酶。目的4重点研究两种新的金黄色葡萄球菌细胞壁水解酶复合体 在未交联肽聚糖进入细胞壁之前对其进行加工。这四个目标将提供 关于细菌细胞壁是如何构建的基本信息。这些研究还将提供新的化学工具， 化验和科学知识使发现可能有助于治疗耐药性的抑制剂成为可能 细菌感染。

Project Summary Antibiotic-resistant bacterial infections pose a substantial and growing threat to human health. There is a pressing need to characterize new antibacterial targets and to develop methods that enable discovery and characterization of inhibitors for these targets. The research described here focuses on understanding late steps in the assembly of the peptidoglycan cell wall that surrounds bacterial cells. The cell wall is essential for bacterial survival, making it an outstanding target for antibiotics. Indeed, some of the most important antibiotics in history, the beta-lactams and the glycopeptides, target late steps in peptidoglycan assembly. Historically, the enzymes that catalyze these late steps have been extremely difficult to study due to the nature of the substrates that are required, the products that are formed, and the fact that many peptidoglycan biosynthetic enzymes are polytopic membrane proteins or function only when complexed to a membrane protein. Recent technological innovations made in our labs have advanced the field of peptidoglycan biosynthesis considerably, and we are able to pursue challenging targets that have not previously been studied. This project has four aims. Aim 1 involves further development of chemical tools to enable mechanistic and structural studies of cell wall biosynthetic enzymes. Aim 2 focuses on understanding MurJ, the flippase that exports the peptidoglycan precursor Lipid II from the cytoplasm to the cell surface where it is polymerized to produce peptidoglycan. Aim 3 focuses on characterizing FtsW, the only universally conserved peptidoglycan polymerase in bacteria. Aim 4 focuses on two novel Staphylococcus aureus cell wall hydrolase complexes that process uncrosslinked peptidoglycan before it is integrated into the cell wall. These four aims will provide fundamental information on how the bacterial cell wall is built. The studies will also provide new chemical tools, assays, and scientific knowledge to enable the discovery of inhibitors that may be useful for treating resistant bacterial infections.