TABLE 2.
Possible conformers of an α2,6-sialoglycan in solution, represented by 6′SLN (Neu5Acα2-6Galβ1-4GlcNAc). The φ dihedral angle (C1-C2-O-C6′) can adopt values of 180° and −60° (t and -g conformers, respectively), whereas the ω torsion angle (O-C6′-C5′-O5’) can explore three values, 180°, 60°, and −60° (tg, gt, and gg conformers, respectively). The ψ dihedral angle (C2-O-C3′-H3′) remains stable at around 180°. The information about each conformer and the corresponding NMR evidence proving their existence was retrieved from Forgione et al. (2020a) and Di Carluccio et al. (2020). The representative structures were generated using the Carbohydrate Builder tool from GLYCAM-web (Woods, 2005), and the images were created using PyMOL 2.4.1 (Schrödinger).
| Φ(C1-C2-O-C6′) | 180° (t conformer) | -60° (-g conformer) | |
|---|---|---|---|
| NMR evidence | H3axNeu5Ac-H6 R/S Gal (Strong/Medium NOE) | H5 Neu5Ac-CH3 GlcNAC (Weak NOE) | |
| Representative structure |
|
|
|
| ω(O-C6′-C5′-O5′) | 180° (tg conformer) | 60° (gt conformer) | −60° (gg conformer) |
| NMR evidence |
|
|
|