Disaccharide conformational maps: 3D contours or 2D plots? Original Research Article

The potential energy surfaces of several α-(1→3)- and β-(1→4)-linked disaccharides were obtained and plotted in terms of energy versus ψ glycosidic angle. These plots were compared to those obtained previously in the way of the usual 3D contour maps, which relate the energy with the two glycosidic angles (φ and ψ). Given the usually small variations of the φ angle in the low-energy regions (at least using mm3), both kinds of graphs lead to similar conclusions concerning flexibility measurements by two different methods and assessment of the effects of sulfation and/or hydroxyl group orientation. Only second-order effects were found with some sulfated disaccharides, not changing the general conclusions. The computational efforts required to produce those plots are smaller, and the plots are easier to interpret. Besides, the conversion of a 3D map into a 2D plot leaves the possibility of constructing 3D maps of carbohydrates including a second variable different to φ, e.g., the second ψ angle of a trisaccharide or the ω angle of a 6-linked disaccharide.