Kavanaugh Logan G, Mahoney Andrew R, Dey Debayan, Wuest William M, Conn Graeme L
Department of Biochemistry, Emory University School of Medicine, Atlanta, GA.
Department of Chemistry, Emory University, Atlanta, GA.
bioRxiv. 2023 Sep 19:2023.03.24.533986. doi: 10.1101/2023.03.24.533986.
The Resistance-Nodulation-Division (RND) efflux pump superfamily is pervasive among Gram-negative pathogens and contributes extensively to clinical antibiotic resistance. The opportunistic pathogen contains 12 RND-type efflux systems, with four contributing to resistance including MexXY-OprM which is uniquely able to export aminoglycosides. At the site of initial substrate recognition, small molecule probes of the inner membrane transporter (e.g., MexY) have potential as important functional tools to understand substrate selectivity and a foundation for developing adjuvant efflux pump inhibitors (EPIs). Here, we optimized the scaffold of berberine, a known but weak MexY EPI, using an high-throughput screen to identify di-berberine conjugates with enhanced synergistic action with aminoglycosides. Further, docking and molecular dynamics simulations of di-berberine conjugates reveal unique contact residues and thus sensitivities of MexY from distinct strains. This work thereby reveals di-berberine conjugates to be useful probes of MexY transporter function and potential leads for EPI development.
耐药-结瘤-分裂（RND）外排泵超家族在革兰氏阴性病原体中广泛存在，并在临床抗生素耐药性中发挥着重要作用。这种机会性病原体包含12种RND型外排系统，其中四种与耐药性有关，包括MexXY-OprM，它能够独特地输出氨基糖苷类药物。在内膜转运蛋白（如MexY）的初始底物识别位点，小分子探针有潜力作为理解底物选择性的重要功能工具，并为开发辅助性外排泵抑制剂（EPI）奠定基础。在此，我们使用高通量筛选优化了小檗碱（一种已知但作用较弱的MexY EPI）的支架结构，以鉴定与氨基糖苷类药物具有增强协同作用的二聚小檗碱缀合物。此外，二聚小檗碱缀合物的对接和分子动力学模拟揭示了独特的接触残基以及不同菌株中MexY的敏感性。这项工作从而揭示了二聚小檗碱缀合物是MexY转运蛋白功能的有用探针以及EPI开发的潜在先导化合物。
