Figure 1.

Ribbon representation of the tertiary structure of human MDR3. (a) The three-dimensional structure of the N-terminal NBD (residues 375–631) built by homology with the structure of the murine multidrug resistance protein 1A is represented with α-helices and β-strands shown in yellow and the connecting loops in red. The C-terminal NBD (residues 1020–1280) is shown in blue. The mutated Leu481 and the two ADP molecules are represented in ball-and-stick. The two TMD α-helices in the vicinity of the Leu481 (residues 884–927) are also shown in green. Carbon, oxygen, nitrogen and phosphorus atoms are colored in gray, red, blue and green, respectively. (b) Region surrounding the p.Leu481Arg mutation, with the neighboring residues represented in ball-and-stick.