Hydrogen bonding patterns define structures in biomolecules. Using a 15N,13C a2,8-linked sialic acid tetramer as a model system at 263K, we detected intra-residue hydrogen bonds between the HN (at C5) and the oxygen atom (at C8) for residues I, II and III of the tetramer. The hydrogen bonds are supported by slower 1H/2H exchange rate for the HNs. We generated two models based on the hydrogen bonds, one with two residues per turn (510 helix) and one with four residues per turn (210 helix). We used the models to obtain interatomic distances and report that the 510 helical model is in better agreement with the experimental NOE data. The models are further supported by heteronuclear coupling between H7 and C2 for residues II and III. Thus, hydrogen bonds can be a determinant factor for shaping the oligosaccharide three dimensional structure.

Hydrogen bonding, the foundations of helicity in a tetramer of α2-8 sialic acid

243rd National Meeting (2012)

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