Project 2: Targeting Gram-positive Cell Envelope Assembly

项目摘要 项目2：革兰氏阳性细胞包膜组装靶向 侵袭性耐甲氧西林金黄色葡萄球菌（MRSA）和耐药肺炎链球菌 在美国，由于抗药性感染， States.据保守估计，每年有90万人感染，这意味着， 在可预见的未来仍将是一个威胁找出这些生物体中新的弱点至关重要 并保持一个目标和化合物的管道，可用于治疗它们引起的感染。在这 建议，我们将在S.金黄色葡萄球菌和肺炎，强调那些 对于屏障完整性至关重要，因为靶向它们可以允许继续使用这些抗生素， 生物体已经产生了广泛的耐药性，例如β-内酰胺类。Aim 1将采用复合驱动 在S. aureus利用了一个创新的平台， 通过基于转座子的管道进行定向化学筛选，以快速识别化合物的靶标， 抑制细胞包膜过程。目标2将采取目标驱动的方法，以促进我们对 LtaS是一种在革兰氏阳性细胞上合成脂磷壁酸的多位膜蛋白， 阳性细胞表面。基于对工具化合物的发现，我们还将鉴定S。金葡菌LtaS 抑制剂使用途径定向筛选方法。目标3将集中在磷壁酸的调节 S.肺炎。脂磷壁酸和壁磷壁酸（WTA）之间的平衡 已经发现该病原体的表面在空间上控制细胞壁水解酶以引导PG的扩增 生长过程中的网状结构。为了防止细菌溶解，必须仔细控制S中的WTA水平。肺炎，a β-内酰胺利用的脆弱性，促进了WTA含量的急剧增加。我们 已经鉴定了一种必需的WTA水解酶（WhyD），当其失活时模拟β-内酰胺处理， 增加WTA水平并诱导细胞溶解。我们将描述这种酶的功能和调节， 研究其作为新自溶诱导治疗靶点的潜力。

PROJECT SUMMARY Project 2: Targeting Gram-positive Cell Envelope Assembly Invasive methicillin-resistant Staphylococcus aureus (MRSA) and drug-resistant Streptococcus pneumoniae infections together are responsible for almost 50% of all deaths due to antibiotic-resistant infections in the United States. Their prevalence, conservatively estimated at a combined 900,000 infections each year, means that they will continue to be a threat for the foreseeable future. It is crucial to identify new vulnerabilities in these organisms and to maintain a pipeline of targets and compounds that can be used to treat the infections they cause. In this proposal, we will pursue cell envelope targets in S. aureus and S. pneumoniae, emphasizing those that are critical for barrier integrity because targeting them could allow continued use of antibiotics to which these organisms have developed widespread resistance, such as beta-lactams. Aim 1 will take a compound-driven approach to new target discovery in S. aureus that exploits an innovative platform that combines pathway- directed chemical screening with a transposon-based pipeline to rapidly identify targets for compounds that inhibit cell envelope processes. Aim 2 will take a target-driven approach that advances our understanding of the mechanism and structure of LtaS, a polytopic membrane protein that synthesizes lipoteichoic acids on the Gram- positive cell surface. Based on discoveries made with a tool compound, we will also identify S. aureus LtaS inhibitors using a pathway-directed screening approach. Aim 3 will focus on the regulation of teichoic acid polymers in S. pneumoniae. The balance between lipoteichoic acids and wall teichoic acids (WTAs) on the surface of this pathogen have been found to spatially control cell wall hydrolases to guide expansion of the PG meshwork during growth. To prevent bacteriolysis, WTA levels must be carefully controlled in S. pneumoniae, a vulnerability exploited by beta-lactams, which promote a dramatic increase in the WTA content of the wall. We have identified an essential WTA hydrolase (WhyD) that when inactivated mimics beta-lactam treatment to increase WTA levels and induce cell lysis. We will characterize the function and regulation of this enzyme and investigate its potential as a novel autolysis-inducing therapeutic target.