Fig. 3. Substrate binding modes of EcOpgD and EcOpgG complex structures.

Hydrogen bonds with distances (Å, red numbers) are shown as yellow dotted lines. a, b Structures around subsite –1 in EcOpgD (a) and EcOpgG (b). Hydrogen bonds on the suggested reaction pathway are shown as blue dotted lines. The electron densities of Wat1, Wat2, and Wat3 are shown as F_o–F_c omit maps by blue meshes at the 3σ contour level. Residues and substrates are shown in green and white sticks, respectively. b EcOpgD (cyan, line representation) superimposed with EcOpgG. c Conformation of the Glc moieties at subsites –1 and +1 in EcOpgD. The innate wild-type residues are shown in parentheses if the residues are substituted.