FIGURE 4.
Two carboxyl groups are important for conferring resistance by BbMAT. A, drug resistance of E. coli cells harboring the indicated BbMAT mutant. Serial dilutions of cells were spotted on plates supplemented with ethidium (100 μg/ml) or acriflavine (100 μg/ml). The plates are representative of at least three independent experiments. B, IC50 values for acriflavine were assessed by calculating the amount of drug required to inhibit cell growth by 50%, as described under “Experimental Procedures.” The experiments were repeated at least twice. C, expression of the different mutants assessed by Coomassie staining. ND, not determined.