Figure 4

Comparison of the AlphaFold model of GLT8D1 with other related GT8 enzymes. The GT-A fold catalytic domain from the GLT8D1 AlphaFold model (AF-Q68CQ7-F1, A and B) was aligned with the related GT8 enzymes, WbbM (panels C and D, PDB 6U4B²³), GlyE (panels E and F, PDB 5GVV²⁴), and the xyloxyltransferase domain of human LARGE-1 (panels G and H, PDB 7UI7²⁵). Panels A, C, E and G are displayed as cartoon representations with gray surface and stick representations for the DxD, G-loop and C-terminal His motifs shown in yellow and bound divalent cation as gray sphere. Panels B, D, F and H are zoomed-in representations of the donor binding site for the respective enzymes. For the zoomed-in representations, a bound UDP-Gal and Mn²⁺ were modeled in the active site (gray stick representation) based on the UDP and Mn²⁺ complex of GlyE and the structure of UDP-Gal from B4GALT1²⁶ (PDB 2FYC). Putative interacting residues were identified in the respective complexes as residues facing the sugar residue of the donor. Yellow sticks are displayed for the DxD motif (yellow labels) and C-terminal His (green labels). The G-loop motif is displayed in magenta and the xED motif residues are displayed in cyan sticks in each panel. Other interacting residues are indicated by thin stick representation with residue labeling.