The quinolones inhibit the essential bacterial enzymes DNA gyrase and topoisomerase IV, which alter DNA topology after inserting a double-stranded break. DNA gyrase exists as an A2B2 tetramer, encoded by the gyrA and gyrB genes, and catalyses negative DNA supercoiling. Topoisomerase IV exists as a C2E2 tetramer encoded by the parC and parE genes, and is involved in chromosome partitioning. Prev...
