Fig. 5.
Ability of ciprofloxacin to compete out DNA cleavage induced by 10 µM 8-methyl-3′-(AM)P-dione with mutant M. tuberculosis gyrase. Results are shown for GyrAA90V (A90V, red) and GyrAD94G (D94G, yellow). Both drugs were added to reaction mixtures simultaneously. The low level of cleavage seen in the presence of ciprofloxacin alone was used as a baseline and was subtracted from DNA scission observed in the presence of both drugs. The level of DNA cleavage observed in the presence of the quinazolinedione alone was set to 1.0 to facilitate direct comparisons. Error bars represent the SD of at least three independent experiments.