title: NMR study of hydroxy and amide protons in hyaluronan polymers.
abstract: Hyaluronan (HA) is an important and well characterized glycosaminoglycan with high viscosity and water-retaining capacity. Nonetheless, it is not fully understood whether conformational properties of the easily characterized HA oligomers can be transferred to HA polymers. To investigate possible differences in hydration, hydrogen bonding and flexibility between HA polymers and oligomers, hydroxy and amide protons of HA polymers were studied by solution-state and high-resolution magic angle spinning (HR-MAS) NMR spectroscopy. Measurements of chemical shifts, temperature coefficients and NOEs in HA polymers revealed that the NMR data are very similar compared to the interior of a HA octasaccharide, supporting transient hydrogen bond interactions across the β(1→3) and β(1→4) glycosidic linkages. However, differences in NOEs suggested a cis-like orientation between NH and H2 in the HA polymer. The lack of concentration dependence of the hydroxy proton chemical shifts suggests that there are no direct inter-chain interactions involving hydroxy protons at the concentrations investigated.
authors.affiliation: Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences P.O. Box 7015, SE-750 07, Uppsala, Sweden. Electronic address: gustav.nestor@slu.se.
authors.forename: Gustav
authors.initials: G
authors.lastname: Nestor
authors.affiliation: Department of Chemistry and Biotechnology, Swedish University of Agricultural Sciences P.O. Box 7015, SE-750 07, Uppsala, Sweden. Electronic address: corine.sandstrom@slu.se.
authors.forename: Corine
authors.initials: C
authors.lastname: Sandström
mesh_terms: D000577:Amides; D006820:Hyaluronic Acid / Q000737:chemistry*; D006860:Hydrogen Bonding; D009682:Magnetic Resonance Spectroscopy; D011108:Polymers; D011522:Protons
chemical_list: D000577:Amides; D011108:Polymers; D011522:Protons; D006820:Hyaluronic Acid
keywords: Hyaluronan; Hydration; Hydrogen bonding; Hydroxy proton; NMR spectroscopy