Figure 3.

Determinants of sugar specificity of plant glycosyltransferases 1 (GT1s). (A) Consensus plant secondary product glycosyltransferase (PSPG) motif generated by weblogo (weblogo.berkeley.edu) from an alignment of characterized GT1s. (B) The sugar donor-binding site for the crystal structure of the GT1 enzyme UGT71G (a flavonoid/triterpenoid O-glucosyltransferase Medicago truncatula) in complex with uridine diphosphate glucose (UDP-Glc) (PDB code 2ACW). The PSPG motif is shown in dark green, the N5 loop in light green, and catalytic residues in dark red. UDP-Glc is shown as a ball and stick model and colored in blue. Proposed hydrogen bonds are shown as dashed lines. (C) Compared structures of most common sugar donors of plant GT1s.