Viomycin is a basic peptide antibiotic, which is among the most effective agents against multidrug-resistant tuberculosis. The tuberactinomycins, such as Viomycin, target bacterial ribosomes, binding RNA and disrupting bacterial protein biosynthesis. Specifically, viomycin binds to a site on the ribosome which lies at the interface between helix 44 of the small ribosomal subunit and helix 69 of the large ribosomal subunit. The structures of this complexes suggest that the viomycin inhibits translocation by stabilizing the tRNA in the A site in the pretranslocation state.