Figure 4

Modeling of the human UGT1A1 protein. (A) Structural alignment of the human UGT1A1 polypeptide with that of UGT71G1. The secondary structure elements are shown above the alignment. The 44-aa donor signature motif of UGT1A1 is enclosed by a cyan box. Broadly conserved hydrophilic and hydrophobic residues are highlighted with degree of conservation shown below the alignment. This panel was produced by the GeneDoc program [82]. (B) Ribbon diagram of the modeled 3D structure of the human UGT1A1. The N- and C-terminal domains are shown in green and orange, respectively. The α helices and β strands in the N- and C-terminal domains are labeled. This panel was made by Swiss-PdbViewer [78]. (C) Stereo diagram showing predicted interactions between the donor UDPGA and the UGT1A1 side chains. Hydrogen bonds are indicated by dashed lines. Figures 4C, 6B, 6C, and 8 were prepared with the Pymol [83].