Uncovering Nonconventional and Conventional Hydrogen Bonds in Oligosaccharides through NMR Experiments and Molecular Modeling: Application to Sialyl Lewis‑X

• Published in: Journal of the American Chemical Society Vol. 137; no. 42; pp. 13444 - 13447
• Main Authors: Battistel, Marcos D, Azurmendi, Hugo F, Frank, Martin, Freedberg, Darón I
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 28-10-2015
• Subjects: Hydrogen Bonding; Magnetic Resonance Spectroscopy; Models, Molecular; Oligosaccharides - chemistry
• ISSN: 0002-7863; 1520-5126
• DOI: 10.1021/jacs.5b03824

We describe the direct NMR detection of a C–H···O nonconventional hydrogen bond (Hbond) and provide experimental and theoretical evidence for conventional Hbonds in the pentasaccharide sialyl Lewis-X (sLeX-5) between 5 and 37 °C in water. Extensive NMR structural studies together with molecular dynamics simulations offer strong evidence for significant local dynamics in the LeX core and for previously undetected conventional Hbonds in rapid equilibrium that modulate structure. These NMR studies also showed temperature-dependent 1H and 13C line broadening. The resulting model emerging from this study is more complex than a simple rigid core description of LeX-like molecules and improves our understanding of stabilizing interactions in glycans.