Structural models of L-type lectins with monoglucosylated high-mannose-type oligosaccharides.

Surface models of (A) ERGIC-53–CRD/MCFD2 and (B) VIP36–CRD are shown with the glucose, mannose, and N-acetylglucosamine residues displayed in magenta, green, and slate stick models, respectively. To model Glc1Man8GlcNAc2, we selected Glc-α1,3–Man coordinates from an insect arylphorin glycoprotein [PDB code: 3GWJ (molecule D)] based on the torsion angle energy estimated using the PDB-CARE program [40]. Other typical Glc-α1,3–Man structures (PDB codes: 3GWJ (molecule A), 3O0W, 3OGV, and 3OG2) with energetically acceptable torsion angles were also superimposed on the ERGIC-53 (A, bottom) and VIP36 (B, bottom) complexes. These coordinates are indicated by thin stick models (glucose: red, mannose: green). The nomenclature of oligosaccharide residues of Glc1Man8GlcNAc2 are shown as in Figure 1A.