Fig. 2. MdrA1 and MdrA2 have sequence similarity to known ABC transporter proteins. The complete nucleotide and derived amino acid sequence of mdrA1 and mdrA2 are available in GenBank as AF246689. The N-terminal and C-terminal ABC transporter domains of MdrA1 and MdrA2 are aligned with the consensus ABC transporter domain from the Pfam protein families database (Bateman et al., 2000). The alignment was done using the program CLUSTAL W (Thompson et al., 1994). Black boxes indicate identical amino acids whereas shaded boxes indicate conservatively substituted residues.