A <i>trans</i> -translation inhibitor kills <i>Mycobacterium tuberculosis</i> by targeting ribosomal protein bL12

New antibiotics with novel mechanisms of action are needed to treat infections by multidrug-resistant strains of <i>Mycobacterium tuberculosis</i> . Here, we show that KKL-1005, an anti-tubercular triazole-based molecule, binds to ribosomal protein bL12 and specifically inhibits the <i>trans</i> -translation ribosome rescue pathway, a process essential for the survival of <i>M. tuberculosis.</i> Our data demonstrate that KKL-1005 binds to the N terminal domain of bL12, both <i>in vitro</i> and in bacterial cells, and specifically inhibits <i>trans</i> -translation and not normal translation. These results suggest that tmRNA-SmpB interacts with bL12 differently from tRNA, and raise the possibility of developing antibiotics targeting bL12.