Figure 3.

UDPGA interacts with multiple residues in the C-terminal domain as well as three residues in the N-terminal domain (S37, R172, and R256). (A) UDPGA docked into the cleft located between the C-terminal (blue ribbons) and N-terminal domains with several interacting residues indicated. (B) 2D schematic diagram of all non-van der Waals UDPGA–UGT1A6 interactions. Classical hydrogen bonds are shown in dark green, nonclassical hydrogen bonds, in which the donor is a polarized carbon atom, are shown in pale green, electrostatic interactions are shown in orange, hydrophobic interactions in pink, with π–π stacking interactions in dark pink and π–alkyl interactions in light pink, and unfavorable donor–donor interactions are shown in red.