Transporter sequence comparison and alkane susceptibility assay of ABC2 and ABC3 mutants. (A) Multiple sequence alignment of NBD2 of ABC transporters. ABC2 [GenBank: CAG82364]; ABC3 [GenBank: CAG82646]; PDR5 [GenBank: CAA99359]; and PDR15 [GenBank: AAB64846]. Starting amino acid numbers are shown in each line. Sequences were aligned in ClustalW, and the shading was created by Mobyle Pasteur Boxshade. Single letter abbreviations for amino acid residues are as follows: A, Ala; C, Cys; D, Asp; E, Glu; F, Phe; G, Gly; H, His; I, Ile; K, Lys; L, Leu; M, Met; N, Asn; P, Pro; Q, Gln; R, Arg; S, Ser; T, Thr; V, Val; W, Trp; and Y, Tyr. (B) Alkane susceptibility assay with ABC2 and ABC3 mutants. Susceptibility assays were performed as described under “Methods”.