title: Two-dimensional J-resolved proton NMR spectroscopy of oligomannosidic glycopeptides.
abstract: Individual anomeric protons that are unresolved in the one-dimensional 250-MHz spectra of oligomannosidic glycopeptides can be separated and characterized by two-dimensional J-resolved NMR spectroscopy. Homogeneous preparations of ovalbumin glycopeptides Man6GlcNAc2Asn and Man5GlcNAc2Asn were characterized by chemical methods, conventional proton NMR, and two-dimensional J-resolved NMR. Due to characteristic differences in coupling constants, mannose (J1,2 less than or equal to 2 Hz) and N-acetylglucosamine (J1,2 approximately 9 Hz) anomeric signals of similar chemical shift were readily separated and identified in the two-dimensional spectra. It is shown that two-dimensional J-resolved NMR spectroscopy, in combination with conventional NMR and limited chemical analysis, is a rapid and reliable technique for the determination of glycopeptide primary structure.
mesh_terms: D000818:Animals; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002645:Chickens; D006020:Glycopeptides / Q000302:isolation & purification*; D009682:Magnetic Resonance Spectroscopy; D008358:Mannose / Q000032:analysis*; D009844:Oligosaccharides; D010047:Ovalbumin
chemical_list: D006020:Glycopeptides; D009844:Oligosaccharides; D010047:Ovalbumin; D008358:Mannose