Replication of Escherichia coli DNA in vitro: inhibition by oxolinic acid

Oxolinic acid, a quinolone antibacterial agent, inhibits reversibly the ATP-dependent replicative DNA synthesis in permeable cell systems as well as in cellophane disk lysates. It is about 10-fold more active than the structurally related nalidixic acid. Both drugs have no effect on the ATP-independent DNA repair, but interfere to some extent with RNA synthesis in permeable cells. They appear to interact with the same target since spontaneous nalidixic-acid-resistant mutants of nalA phenotype are also resistant to oxolinic acid. Full sensitivity to oxolinic acid can be conferred to lysates from resistant cells by addition of extracts from sensitive cells.