Fig. 3.

Effects of Mg²⁺ concentration on DNA cleavage mediated by WT and mutant M. tuberculosis gyrase. Results are shown for 10 µM ciprofloxacin (Left) and 10 µM 8-methyl-3′-(AM)P-dione (Right) with WT (black), GyrA^A90S (A90S, blue), and GyrA^A90V (A90V, red). DNA cleavage for each drug–enzyme pair was normalized to 100% at 6 mM Mg²⁺ to facilitate direct comparisons. Error bars represent the SD of at least three independent experiments.