Fig. 4.

Conformational analysis for hexasaccharide 30. The two possible populations around ψ torsion angle of (a) the α-(1 → 2)- and (b) the α-(1 → 3)-glycosidic linkages. The distances between the key inter-residue protons are highlighted. Population 1 is the major one for both a1 α-(1 → 2)- and α–(1 → 3)-linkages according to NOE data. (c) Perspective of the major conformation proposed for 30 based on the experimentally observed NOEs and the geometry models taken from MD simulations. A bent shape is present for the terminal Man-α-(1 → 2)-Man-α–(1 → 3)-Man moiety. The observed NOEs are basically identical in the presence of DC-SIGN, strongly suggesting that this is also the preferred bound conformation.