摘要

在红霉素抗性细菌中，23S rRNA中A2058的N6位由Erm家族甲基转移酶单或二甲基化。这种修饰导致对大环内酯类，林可酰胺类和链球菌素B的交叉耐药性.Emm甲基转移酶的大多数抑制剂最新开发靶向辅因子结合口袋，导致缺乏选择性，而结合底物结合口袋的抑制剂表现出低体外活性。在此研究中，采用分子对接方法进行生物化学筛选，以寻找针对ErmC'甲基转移酶的辅因子和底物结合口袋的抑制剂。基于ZINC数据库清洁引导子集的基于分子对接的虚拟筛选结果，选择了29种化合物用于实验验证。其中抑制剂28（ZINC代码32747906），IC50为100μM，降低了过表达ErmC'的大肠杆菌菌株中红霉素的最小抑制浓度。对ErmC'结构和竞争性配体结合测定的对接分析揭示了非竞争性抑制模型。抑制剂28作为基于相似性的虚拟筛选的模板，其导致识别两种衍生物3s（ZINC码62022572）和4s（ZINC码49032257），其IC50分别为116μM和110μM。我们的研究结果为开发针对Erm家族酶的抑制剂提供了基础。

In erythromycin–resistant bacteria, the N6 position of A2058 in 23S rRNA is mono– or dimethylated by Erm family methyltransferases. This modification results in cross–resistanceto macrolides, lincosamides and streptogramin B. Most inhibitors of Erm methyltransferases developed up–to–date target the cofactor–binding pocket, resulting in a lack of selectivity whereas inhibitors that bind the substrate–binding pocket demonstrate low in vitro activity. In this study, a molecular docking approach followed by biochemical screening was applied to search for inhibitors targeting both cofactor– and substrate–binding pockets of ErmC′ methyltransferase. Based on the results of the molecular docking–based virtual screening of the clean–leads subset of the ZINC database, 29 compounds were chosen for experimental verification. Among them inhibitor 28 (ZINC code 32747906), with an IC50 of 100 μM, decreased the minimal inhibitory concentration of erythromycin in the Escherichia coli strain overexpressing ErmC'. Docking analysis of 28 to the ErmC′ structure and the competitiveligand binding assay revealed a non–competitive model of inhibition. Inhibitor 28 served as a template for similarity–based virtual screening, which resulted in the identification of two derivatives 3s (ZINC code 62022572) and 4s (ZINC code 49032257) with an IC50 of 116 μM and 110 μM, respectively. Our results provide a basis for the development of inhibitors against the Erm–family of enzymes.

https://www.sciencedirect.com/science/article/pii/S0223523417309352