Fig. 1.

Structural information of IspS from gray poplar with the substrate DMAPP and the co-factor Mg²⁺. a Information of the two identified active motifs and special residues. The N-terminal domain (yellow) and the active domain (gray) are displayed. The conserved DDXXD motif (red) and the NSE/DTE motif (red) are located in the active C-terminal domain. The substrate DMAPP (blue) and three Mg²⁺ co-factors (green) are located between the motifs. The three special residues (dark), F338, V341, and F485, are located just outside of the active pocket and supposedly reduce the size of the substrate-binding site. b Interaction of particular residues with DMAPP and Mg²⁺. Three different views are shown. The interactions between DMAPP and residues are indicated with gray dashed lines. The interactions between Mg²⁺ and DMAPP or residues are indicated with purple dashed lines. The PDB number of the IspS from gray poplar is 3N0G