Targeting MraY: Synthesis and Validation of MraY Inhibitors

描述（由申请人提供）：一种天然来源的MraY抑制剂，卡普霉素，在结核分枝杆菌小鼠感染模型中显示出显著的体内活性。muraymycin具有卡普霉素的共同核心结构，然而，它们的结构多样性是在无环复合物沉积肽段和C5'-糖附加部分中观察到的。wyeth研究小组强调了muraymycin A1对金黄色葡萄球菌的体内抗菌活性。因此，验证穆拉霉素A1在体外和体内对结核分枝杆菌的疗效是我们感兴趣的。然而，用于产生muraymycin A1的真菌菌株（Streptomyces spp. l - aa896）和任何同系物都没有，必须合成muraymycin A1进行体外化合物分析。因此，我们将建立完整的muraymycin A1的合成路线，以获得足够的分子（Specific Aim 1）。此外，muraymycin A1和capuramycin的药物化学计划旨在提高包括药代动力学在内的疗效，但这些计划受到以下因素的阻碍：1)这些结构的复杂性；2)难以选择性地对所需位置进行化学修饰；3)无法方便地检测Mtb MraY酶，包括难以获得足够的MraY底物，Park's核苷酸。我们完成了Park's核苷酸及其荧光探针的可扩展化学酶和全合成，并建立了一种方便的MraY抑制剂测定方法，使用富含MraY， MurG和decaprenylphosphate的细胞膜组分。此外，在过去的几年里，我们在含尿苷氨基醇分子在溶液或聚合物载体上的合成可及性方面获得了广泛的知识。我们将继续设计和合成新的尿嘧啶-氨基醇衍生物，以确定鼠霉素和卡普霉素的最小和基本结构（具体目标2）。将在科罗拉多州立大学分枝杆菌研究实验室（Specific Aim 3）对生成的抗Mtb MraY和对药物敏感和耐药的结核分枝杆菌分子进行体外分析。

DESCRIPTION (provided by applicant): A MraY inhibitor from a natural source, capuramycin, exhibited significant activity in vivo using M. tuberculosis mouse infection model. Muraymycins possess a common core structure of capuramycin, however, their structural diversity is observed in an acyclic complex depsipeptide moiety and the C5'-sugar-appended. Promising in vivo antibactericidal activity of muraymycin A1 against S. aureus was highlighted by the Wyeth-Research groups. Thus, it is of our interest to validate the efficacy of muraymycin A1 in vitro and in vivo against M. tuberculosis. However, the fungus strain (Streptomyces spp. LL-AA896) used to produce muraymycin A1 and any congeners are not available, and muraymycin A1 has to be synthesized for the in vitro compound profiling. Thus, we will establish the synthetic route for intact muraymycin A1 to obtain enough molecules (Specific Aim 1). Furthermore, medicinal chemistry programs of muraymycin A1 and capuramycin with an aim to improve the efficacy including pharmacokinetics are hampered by 1) the complexity of these structures, 2) difficulty in chemically modifying the desired positions selectively, and 3) no convenient assay against Mtb MraY enzyme including difficulty in obtaining enough MraY substrate, Park's nucleotide. We accomplished a scalable chemoenzymatic and total synthesis of Park's nucleotide and its fluorescent probe, and established a convenient MraY inhibitor assay using a cell envelop enriched fraction including MraY, MurG and decaprenylphosphate. In addition, over the past years we obtained extensive knowledge of synthetic accessibility of uridine-amino-alcohol containing molecules in solution or on the polymer- support. We will continue designing and synthesizing new uridine-amino-alcohol derivatives in order to identify the minimal and essential structures of muraymycins and capuramycin (Specific Aim 2). In vitro profiling of the generated molecules against Mtb MraY and drug-sensitive and -resistant M. tuberculosis will be performed at the CSU Mycobacteria Research Laboratory (Specific Aim 3). PUBLIC HEALTH RELEVANCE: Multidrug resistant Mycobacterium tuberculosis (MDR-TB) has occurred in hospitals and correctional facilities, and frequently in HIV-infected patient. Clinical responses of MDR- TB patient to currently available drugs have been poor, and in some cases there is no response at all. The long term goal of this grant submission is to develop new drug leads for MDR-TB.