Carbohydrate dynamics at a micellar surface: GD1a headgroup transformations revealed by NMR spectroscopy.
The conformational dynamics of the carbohydrate headgroup of ganglioside GD1a, NeuAc alpha 2-->3Gal beta 1-->3GalNAc beta 1-->4[NeuAc alpha 2-->3]Gal beta 1-->4Glc beta 1-->1Cer, anchored in a perdeuterated dodecylphosphocholine micelle in aqueous solution, were probed by high resolution NMR spectroscopy. The observed 1H/1H NOE interactions revealed conformational averaging of the terminal NeuAc alpha 2-->3Gal and Gal beta 1-->3GalNAc glycosidic linkages. The pronounced flexibility of this trisaccharide moiety was substantiated further by two-dimensional proton-detected 13C T1, T1 rho and 1H/13C NOE measurements. The anchoring effect of the micelle allowed the detection of conformational fluctuations of the headgroup on the time scale of a few hundred picoseconds. NMR experiments performed on the GD1a/DPC micelles in H2O at low temperatures permitted the observation of hydroxyl proton resonances, contributing valuable conformational information.
Poppe
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Complex Carbohydrate Research Center, University of Georgia, Athens 30602.
van Halbeek
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Acquotti
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Sonnino
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D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002417:Cattle; D005732:Gangliosides / Q000737:chemistry*; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D008823:Micelles; D008958:Models, Molecular; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010767:Phosphorylcholine / Q000031:analogs & derivatives; D012996:Solutions; D013816:Thermodynamics; D014867:Water
D005732:Gangliosides; D008823:Micelles; D012996:Solutions; D014867:Water; D010767:Phosphorylcholine; C021298:ganglioside, GD1a; C028810:dodecylphosphocholine