A common cause of resistance to kanamycin (KAN) in tuberculosis is overexpression of the enhanced intracellular survival (Eis) protein. Eis is an acetyltransferase that multiacetylates KAN and other aminoglycosides, rendering them unable to bind the bacterial ribosome. By high-throughput screening, a series of substituted 1,2,4-triazino[5,6b]indole-3-thioether molecules were identified as effective Eis inhibitors. Herein, we purchased 17 and synthesized 22 new compounds, evaluated their potency, and characterized their steady-state kinetics. Four inhibitors were found not only to inhibit Eis in vitro, but also to act as adjuvants of KAN and partially restore KAN sensitivity in a Mycobacterium tuberculosis KAN-resistant strain in which Eis is upregulated. A crystal structure of Eis in complex with a potent inhibitor and CoA shows that the inhibitors bind in the aminoglycoside binding site snugly inserted into a hydrophobic cavity. These inhibitors will undergo preclinical development as novel KAN adjuvant therapies to treat KAN-resistant tuberculosis.

中文翻译：

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结核分枝杆菌卡那霉素抗性酶Eis的有效1,2,4-三嗪[5,6 b ]吲哚-3-硫醚抑制剂

结核病中对卡那霉素（KAN）耐药的常见原因是增强的细胞内存活（Eis）蛋白的过表达。Eis是一种乙酰基转移酶，可将KAN和其他氨基糖苷多乙酰化，使其无法结合细菌核糖体。通过高通量筛选，一系列取代的1,2,4-三嗪并[5,6 b ]吲哚-3-硫醚分子被确定为有效的Eis抑制剂。在这里，我们购买了17种化合物并合成了22种新化合物，评估了它们的效能，并表征了它们的稳态动力学。在结核分枝杆菌中发现四种抑制剂不仅可以体外抑制Eis ，而且可以作为KAN的佐剂和部分恢复KAN的敏感性。Eis上调的KAN抗性菌株。Eis与有效抑制剂和CoA复合的晶体结构表明，抑制剂结合在紧紧插入疏水腔中的氨基糖苷结合位点。这些抑制剂将作为新的KAN辅助疗法进行临床前开发，以治疗耐KAN的结核病。