Nuclear Magnetic Resonance Methods in Structural Characterization of Glycosaminoglycans.

Glycosaminoglycans (GAGs) are sulfated glycans of complex structure and multiple biological actions. They are composed of disaccharide repeating units of alternating uronic acid/galactose and hexosamine. Sulfation patterns are an additional structural variation of these polymers. Nuclear magnetic resonance (NMR) spectroscopy is one of the most powerful analytical techniques employed in structural analysis of GAGs. 1D and 2D NMR spectra, both homonuclear 1H and heteronuclear 1H-13C, are the commonest NMR methods used. This chapter describes the overall experimental methods and materials necessary for adequate preparation of GAG samples for NMR investigations aimed to unveil the main structural characteristics of these biomacromolecules. The NMR methods discussed here cover all three isotopes (1H, 13C, and 15N) that can be exploited in structural analysis of GAGs. These NMR methods are described from an overall standpoint, to be applied to any GAG family, extracted from either natural or synthetic sources and destined to either basic research or pharmaceutical applications.