Fig. 2.
Crystal structures of Fab 2G12 in complex with D-fructose, C-6 methyl monosaccharide 10 and C-6′″ methyl tetrasaccharide 5. (A) Fo–Fc simulated annealing omit map of D-fructose bound to Fab 2G12 contoured at 3σ. The light and heavy chains of Fab 2G12 are shown in green and purple, respectively, and the CDR loops are labeled. (B) Overlay of D-fructose (shown in yellow) with Manα1-2Man (shown in blue) from a previous Fab 2G12 structure (11). Additional direct and water-mediated H bonds (H bonds are shown as black dashed lines; waters are shown as pink spheres) in the Fab 2G12/D-fructose structure are shown. (C) Fo–Fc simulated annealing omit map of C-6 methyl monosaccharide 10 (shown in stick format) bound to Fab 2G12 contoured at 3σ. (D) Overlay of the modified monosaccharide (shown in yellow) with Manα1-2Man (shown in blue) (11). Additional water-mediated H bonds in the Fab 2G12/C-6 methyl monosaccharide 10 structure are shown. (E) Fo–Fc simulated annealing omit map of C-6′″ methyl tetrasaccharide 5 bound to Fab 2G12 contoured at 2.5σ. (F) Overlay of the modified tetrasaccharide (shown in yellow) with the D1 arm of Man7 (shown in blue) (23). The mannose residues are labeled. Figure was made using PyMOL (52).