CYP121 of Mycobacterium tuberculosis (Mtb) is an essential target for the development of novel potent drugs against tuberculosis (TB). Besides known antifungal azoles, further compounds of the azole class were recently identified as CYP121 inhibitors with antimycobacterial activity. Herein, we report the screening of a similarity-oriented library based on the former hit compound, the evaluation of affinity toward CYP121, and activity against M. bovis BCG. The results enabled a comprehensive SAR study, which was extended through the synthesis of promising compounds and led to the identification of favorable features for affinity and/or activity and hit compounds with 2.7-fold improved potency. Mode of action studies show that the hit compounds inhibit substrate conversion and highlighted CYP121 as the main antimycobacterial target of our compounds. Exemplified complex crystal structures of CYP121 with three inhibitors reveal a common binding site. Engaging in both hydrophobic interactions as well as hydrogen bonding to the sixth iron ligand, our compounds block a solvent channel leading to the active site heme. Additionally, we report the first CYP inhibitors that are able to reduce the intracellular replication of M. bovis BCG in macrophages, emphasizing their potential as future drug candidates against TB.

中文翻译：

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构效关系和作用模式研究强调 1-(4-联苯甲基)-1H-咪唑衍生的小分子是有效的 CYP121 抑制剂

结核分枝杆菌(Mtb) 的CYP121是开发新型强效抗结核药物 (TB) 的重要靶标。除了已知的抗真菌唑类药物外，最近还发现其他唑类化合物是具有抗分枝杆菌活性的 CYP121 抑制剂。在此，我们报告了基于前命中化合物的相似性导向库的筛选、对 CYP121 亲和力的评估以及对牛分枝杆菌的活性卡介苗。该结果促成了一项全面的 SAR 研究，该研究通过合成有前景的化合物进行了扩展，并导致确定了亲和力和/或活性的有利特征，并击中了效力提高 2.7 倍的化合物。作用模式研究表明，命中化合物抑制底物转化，并强调 CYP121 是我们化合物的主要抗分枝杆菌靶标。具有三种抑制剂的 CYP121 的示例复杂晶体结构揭示了一个共同的结合位点。我们的化合物参与疏水相互作用以及与第六个铁配体的氢键合，阻断了通向活性位点血红素的溶剂通道。此外，我们报告了第一个能够减少牛分枝杆菌 BCG细胞内复制的 CYP 抑制剂在巨噬细胞中，强调它们作为未来抗结核药物的潜力。