Thiostrepton is a macrocyclic antibiotic incorporating thiazoles and other atypical amino acids. Patented in 1961, thiostrepton has been used as an antibiotic and acts by binding to ribosomes to prevent the binding of the EF-G elongation factor and GTP to the 50S ribosomal subunit. Thiostrepton is an inducer oftipA, a gene that controls the bacterial transcription regulators, andtipAL andtipAS, that are central regulators in multidrug resistance. Thiostrepton is closely related to siomycin, a recently discovered inhibitor of oncogenic transcription factor, FoxM1.