FIGURE 7.

Predicted binding positions of compound Y₆ with the human ABCG2 transporter protein. (A) A two-dimensional ligand–receptor interaction diagram shows the important interactions of compound Y₆ with the binding site residues of human ABCG2. The amino acids are shown as colored bubbles, cyan indicates polar residues and green indicates hydrophobic residues. Hydrogen bonds are indicated by the purple arrow. (B) Docked position of compound Y₆ within the binding site of the human ABCG2 transporter protein. Compound Y₆ is shown as a ball and stick model, with the atoms colored as follows: carbon = cyan, hydrogen = white, and oxygen = red. The carbons of the important residues are indicated by the gray color while the other atoms are depicted as sticks with the same color scheme as above and nitrogen is indicated by the blue color. Hydrogen bonds are indicated by dotted yellow lines.