Identification of Novel Dual-targeting Inhibitors of <i>Mycobacterium tuberculosis</i> Aminoacyl-tRNA Synthetases

<b>Background:</b> Tuberculosis is a life-threatening infectious disease and a serious public problem. The recent emergence of extensively and totally resistant strains of <i>Mycobacterium tuberculosis</i> provides the stimulus for the search of novel antituberculosis agents with unexploited mechanisms of action. <b>Objective:</b> The main aim of this study is to develop inhibitors with dual-targeted activity toward <i>M. tuberculosis</i> leucyl-tRNA synthetase (LeuRS) and methionyl-tRNA synthetase (MetRS). <b>Methods: </b>In order to find <i>M. tuberculosis </i>LeuRS and MetRS inhibitors, virtual screening experiments were carried out using AutoDock software. Best-scored compounds were tested<i> in vitro</i> in aminoacylation assay using radioactive [14C]-L-leucine. <b>Results:</b> Small-molecular inhibitors of <i>M. tuberculosis </i>LeuRS were identified among Benzo[b]oxepine-4-carboxylic acid (5-benzyl-thiazol-2-yl)-amide derivatives. The most active compound – 7-Methoxy-benzo[b]oxepine-4-carboxylic acid [5-(2-fluoro-benzyl)-thiazol-2-yl]-amide, inhibits mycobacterial LeuRS with IC₅₀ value of 19.7 µM. It was found that this compound inhibits <i>M. tuberculosis </i>MetRS by 96.5% at the concentration of 100 µM. According to molecular docking results, the compounds in this class interact simultaneously with adenine-acceptor region and amino acid-binding region of <i>M. tuberculosis</i> aminoacyl-tRNA synthetases synthetic sites. <b>Conclusion</b>: Benzo[b]oxepine-4-carboxylic acid (5-benzyl-thiazol-2-yl)-amide derivatives can be used for further structural optimization and biological research.