Fig. 3
From: Molecular basis of human CD22 function and therapeutic targeting
CD22 specificity for the α2-6 glycosidic linkage. a Sia and Gal moieties (green) of the α2-6 sialyllactose ligand extensively H-bond (black dashed lines) with human CD22 (gray). b Schematic representation of the CD22-Neu5Acα(2-6)Gal interaction network. Surface exposed residues are contoured with gray dashed lines. Pink circles with black outline: polar residues, with red outline: acidic residues, with blue outline: basic residues. Green circles represent hydrophobic residues. H-bonds implicating side chains are presented as green dashed lines, and implicating main chain atoms in blue dashed lines. Rendering generated with MOE54. c Specificity for the α2-6 glycosidic linkage is largely due to residues Y64 and R131 (left). Glycans with α2-3 linkages would clash (overlapping dotted spheres) with Y64 (right). d Modeling of Sia-Gal-GlcNAc-Man (cyan surface) reveals that the CD22 C1/C2 β-hairpin is optimally configured to extensively interact with the branch of a complex N-glycan of α2-6 glycosidic linkage. The dashed cyan line indicates the direction of the continued glycan branch
