FIGURE 1.

BbMAT is a multidrug resistance transporter homologous to rVMAT2. A, sequence alignment of key regions demonstrating the conservation between rVMAT2 and BbMAT. The alignment is colored according to the chemical properties of the residues: aliphatic (Ala, Gly, Ile, Leu, Met, Pro, and Val) in pale yellow, polar uncharged (Asn, Gln, Ser, and Thr) in teal, aromatic (Phe, Trp, and Tyr) in yellow/orange, acidic (Asp and Glu) in red, basic (Lys and Arg) in blue, His in pale green, and Cys in gray. Red rectangles mark the MFS and DHA12 motifs (10, 25). Arrows indicate residues studied in this work. B, BbMAT confers resistance against ethidium, MPP⁺, and acriflavine. E. coli JM109 cells harboring BbMAT or empty vector were assayed for drug resistance. 4.5 μl of serial 10-fold dilutions of cells were spotted on plates supplemented with ethidium (100 μg/ml), MPP⁺ (3 mm), or acriflavine (100 μg/ml). The plates are representative of at least three independent experiments.