Quinolone-mediated DNA cleavage by M. leprae DNA gyrase. Supercoiled pBR322 DNA (0.4 μg) was incubated with the M. leprae GyrA (300 ng) and GyrB (250 ng) proteins in the presence of ATP and of moxifloxacin (MXF), gatifloxacin (GAT), or ofloxacin (OFX) at the indicated concentration (in μg/ml). After addition of SDS and proteinase K, the DNA samples were analyzed by electrophoresis in 1% agarose. Lane a, supercoiled pBR322 DNA; R, N, and S, relaxed, nicked, and supercoiled DNA, respectively.