Novobiocin is an aminocoumarin antibiotic that is produced by Streptomyces niveus. Along with other aminocoumarin antibiotics, novobiocin is a very potent inhibitor of bacterial DNA gyrase. It works by targeting the GyrB subunit of the enzyme involved in energy transduction. Novo-TRX is Texas Red-labeled novobiocin, which can be used as a fluorescence probe in assays for screening DNA gyrase inhibitors.