Owing to the emergence of antibiotic resistance, the polymyxin colistin has been recently revived to treat acute, multidrug-resistant Gram-negative bacterial infections. Positively charged colistin binds to negatively charged lipids and damages the outer membrane of Gram-negative bacteria. However, the MCR-1 protein, encoded by the mobile colistin resistance (mcr) gene, is involved in bacterial colistin resistance by catalysing phosphoethanolamine (PEA) transfer onto lipid A, neutralising its negative charge, and thereby reducing its interaction with colistin. Our preliminary results showed that treatment with a reference pyrazolone compound significantly reduced colistin minimal inhibitory concentrations in Escherichia coli expressing mcr-1 mediated colistin resistance (Hanpaibool et al. in ACS Omega, 2023). A docking-MD combination was used in an ensemble-based docking approach to identify further pyrazolone compounds as candidate MCR-1 inhibitors. Docking simulations revealed that 13/28 of the pyrazolone compounds tested are predicted to have lower binding free energies than the reference compound. Four of these were chosen for in vitro testing, with the results demonstrating that all the compounds tested could lower colistin MICs in an E. coli strain carrying the mcr-1 gene. Docking of pyrazolones into the MCR-1 active site reveals residues that are implicated in ligand–protein interactions, particularly E246, T285, H395, H466, and H478, which are located in the MCR-1 active site and which participate in interactions with MCR-1 in ≥ 8/10 of the lowest energy complexes. This study establishes pyrazolone-induced colistin susceptibility in E. coli carrying the mcr-1 gene, providing a method for the development of novel treatments against colistin-resistant bacteria.

由于抗生素耐药性的出现，多粘菌素粘菌素最近重新用于治疗急性、多重耐药的革兰氏阴性细菌感染。带正电荷的粘菌素与带负电荷的脂质结合并损害革兰氏阴性细菌的外膜。然而，由移动粘菌素抗性 ( mcr ) 基因编码的MCR-1 蛋白通过催化磷酸乙醇胺 (PEA) 转移到脂质 A 上，中和其负电荷，从而减少其与粘菌素的相互作用，从而参与细菌粘菌素抗性。我们的初步结果表明，用参考吡唑啉酮化合物处理可显着降低表达mcr-1介导的粘菌素耐药性的大肠杆菌中的粘菌素最小抑制浓度（ACS Omega 中的 Hanpaibool 等人，2023）。对接-MD 组合用于基于整体的对接方法，以进一步鉴定作为候选 MCR-1 抑制剂的吡唑啉酮化合物。对接模拟显示，预计 13/28 所测试的吡唑啉酮化合物的结合自由能低于参考化合物。选择其中四种进行体外测试，结果表明所有测试的化合物都可以降低携带mcr-1基因的大肠杆菌菌株中的粘菌素 MIC 。将吡唑啉酮对接至 MCR-1 活性位点揭示了与配体-蛋白质相互作用有关的残基，特别是 E246、T285、H395、H466 和 H478，它们位于 MCR-1 活性位点并参与与 MCR 的相互作用-1 ≥ 8/10 的最低能量复合体。本研究确定了大肠杆菌中吡唑酮诱导的粘菌素敏感性。携带mcr-1基因的大肠杆菌，为开发针对粘菌素耐药细菌的新疗法提供了一种方法。