Synthesis and Evaluation of Narrow-Spectrum Antibiotics Targeting MRSA

项目摘要/摘要 天然产品占抗菌药典的三分之二，因此享有特权。 脚手架。这些复杂的分子启发了新的合成方法，并对该领域产生了积极影响 生物化学、分子生物学和医学。拟议的项目的灵感来自于白环素，一种 独一无二的14元大内酯，具有强大的窄谱抗“超级细菌”甲氧西林的活性- 耐药金黄色葡萄球菌(MRSA)。我们已经证实白环素对耐甲氧西林金黄色葡萄球菌和 对万古霉素耐药的金黄色葡萄球菌菌株；此外，它对人体细胞无毒。 2013年，Tomoda报告说，白环素在体内抑制了肽聚糖(即细菌细胞壁)的合成 大分子分析。利用生化分析和分子模拟，我们证明了白环素 是金黄色葡萄球菌Mura的弱(MM)抑制物。与其窄谱图谱一致的是，白环素 不能抑制来自E.Coli的Mura。根据我们和Tomoda的结果，我们得出结论，它肯定有额外的 细菌靶标。值得注意的是，我们最近完成了一种模块化的、高效的自然全合成 由N-亚磺基金属二烯胺的新化学驱动的产品。因此，在目标1中，我们建议 半全合成和分流全合成制备白环素类似物(包括探针) 关于这个特权的绞刑架的空间。在目标2中，我们将在阿博环素与Mura的络合物中共结晶 令人振奋的初步结果，并采用基于结构的模拟设计。我们还将确定目标(S) 利用计算化学、化学蛋白质组学和基因组学确定白环素的作用模式 除了一种新的代谢标记方法外，还有一种新的方法。最后，在目标3中，我们将评估 所有白环素类似物的生物活性。 在四年的项目期结束时，我们将对(1)白环素如何 发挥其抗菌作用；(2)工具化合物和抗生素候选化合物库，选择性地 调整他们的目标(S)；最重要的是，(3)小说发展的真正起点， 治疗顽固性MRSA、VISA和VRSA的窄谱抗生素(即该项目的长期目标)。

Project Summary/Abstract Natural products account for two-thirds of the antibacterial pharmacopeia and are therefore privileged scaffolds. These complex molecules have inspired novel synthetic methods and positively impacted the fields of biochemistry, molecular biology, and medicine. The proposed project is inspired by albocycline, a unique 14-membered macrolactone with potent, narrow-spectrum activity against the “superbug” methicillin- resistant Staphylococcus aureus (MRSA). We have validated that albocycline is effective against MRSA and vancomycin-resistant S. aureus strains; moreover, it is non-toxic to human cells. In 2013, Tomoda reported that albocycline inhibited peptidoglycan (i.e., bacterial cell wall) synthesis in macromolecular assays. Using biochemical assays and molecular modeling, we demonstrated that albocycline was a weak (mM) inhibitor of MurA from S. aureus. Consistent with its narrow-spectrum profile, albocycline did not inhibit MurA from E. coli. Based on our results and those of Tomoda, we conclude it must have additional bacterial targets. Significantly, we recently completed a modular, step-efficient total synthesis of the natural product driven by novel chemistry of N-sulfinyl metallodienamines. Accordingly, in Aim 1 we propose to prepare albocycline analogs (including probes) by semi- and diverted total synthesis to explore the chemical space about this privileged scaffold. In Aim 2, we will co-crystallize albocycline in complex with MurA based on exciting preliminary results and employ structure-based analog design. We will also identify the target(s) of albocycline to determine its mode-of-action using computational chemistry, chemical proteomics and genomics approaches, in addition to a novel metabolic labeling methodology. Finally, in Aim 3 we will evaluate the biological activity of all albocycline analogs. At the end of the four-year project period, we will have (1) a deeper understanding of how albocycline exerts its antibacterial action; (2) a library of tool compounds and antibiotic lead candidates that selectively modulate their target(s); and most significantly, (3) a bona fide launching point for the development of novel, narrow-spectrum antibiotics to treat recalcitrant MRSA, VISA, and VRSA (i.e., the project's long-term goal).