FadD32, a fatty acyl-AMP ligase, plays an indispensable role in mycobacterial mycolic acid synthesis and is a validated target for tuberculosis (TB) drug development. The crystal structure of Mycobacterium tuberculosis (Mtb)FadD32 has laid the foundation of structure-based drug discovery against this crucial enzyme. Here, we screened the “isoxazole” scaffold containing molecules against MtbFadD32 and identified a compound 2,4-dibromo-6-[3-(trifluoromethyl)-1,2-oxazol-5-yl]phenol (M1) with specific inhibitory activity against Mtb. Kinetics experiments showed that M1 inhibits MtbFadD32 and MtbFadD28 activity. The transcriptomics response of Mtb disclosed M1-mediated regulation of mycobacterial decisive genes involved in cell wall synthesis, consequently creating unfavorable conditions for Mtb survival. Further, M1 curtails the Mtb survival in infected macrophages and reduces Mtb burden and tubercular granulomas in a chronic infection model of BALB/c mice. Our findings provide an effective chemical scaffold to inhibit MtbFadD32 with the potential to inhibit multiple MtbFadD family of enzymes for further development as a promising candidate for treating TB.

中文翻译：

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鉴定异恶唑衍生物作为靶向结核分枝杆菌 FadD 酶的抗结核化合物


FadD32 是一种脂肪酰基-AMP 连接酶，在分枝杆菌分枝杆菌酸合成中起着不可或缺的作用，是结核病 （TB） 药物开发的验证靶标。结核分枝杆菌 （Mtb）FadD32 的晶体结构为针对这种关键酶的基于结构的药物发现奠定了基础。在这里，我们筛选了含有针对 MtbFadD32 的“异恶唑”支架分子，并鉴定了一种化合物 2,4-二溴-6-[3-（三氟甲基）-1,2-噁唑-5-基]苯酚 （M1），对 Mtb 具有特异性抑制活性。动力学实验表明，M1 抑制 MtbFadD32 和 MtbFadD28 活性。Mtb 的转录组学反应揭示了 M1 介导的参与细胞壁合成的分枝杆菌决定基因的调节，从而为 Mtb 的存活创造了不利的条件。此外，M1 减少了受感染巨噬细胞中的 Mtb 存活率，并减少了 BALB/c 小鼠慢性感染模型中的 Mtb 负荷和结核肉芽肿。我们的研究结果提供了一种有效的化学支架来抑制 MtbFadD32，并有可能抑制多个 MtbFadD 酶家族，以便进一步开发为治疗结核病的有前途的候选者。