title: Analysis of chain and blood group type and branching pattern of sialylated oligosaccharides by negative ion electrospray tandem mass spectrometry.
abstract: We previously reported sequence determination of neutral oligosaccharides by negative ion electrospray tandem mass spectrometry on a quadrupole-orthogonal time-of-flight instrument with high sensitivity and without the need of derivatization. In the present report, we extend our strategies to sialylated oligosaccharides for analysis of chain and blood group types together with branching patterns. A main feature in the negative ion mass spectrometry approach is the unique double glycosidic cleavage induced by 3-glycosidic substitution, producing characteristic D-type fragments which can be used to distinguish the type 1 and type 2 chains, the blood group related Lewis determinants, 3,6-disubstituted core branching patterns, and to assign the structural details of each of the branches. Twenty mono- and disialylated linear and branched oligosaccharides were used for the investigation, and the sensitivity achieved is in the femtomole range. To demonstrate the efficacy of the strategy, we have determined a novel complex disialylated and monofucosylated tridecasaccharide that is based on the lacto-N-decaose core. The structure and sequence assignment was corroborated by methylation analysis and 1H NMR spectroscopy.
authors.affiliation: MRC Glycosciences Laboratory, Faculty of Medicine, Imperial College London, Northwick Park and St Mark's Campus, Harrow, Middlesex, UK. w.chai@imperial.ac.uk
authors.forename: Wengang
authors.initials: W
authors.lastname: Chai
authors.forename: Vladimir E
authors.initials: VE
authors.lastname: Piskarev
authors.forename: Barbara
authors.initials: B
authors.lastname: Mulloy
authors.forename: Yan
authors.initials: Y
authors.lastname: Liu
authors.forename: Philip G
authors.initials: PG
authors.lastname: Evans
authors.forename: Helen M I
authors.initials: HM
authors.lastname: Osborn
authors.forename: Alexander M
authors.initials: AM
authors.lastname: Lawson
mesh_terms: D001789:Blood Group Antigens / Q000032:analysis*; D001788:Blood Grouping and Crossmatching / Q000379:methods*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008745:Methylation; D019158:N-Acetylneuraminic Acid; D025942:Oligosaccharides, Branched-Chain / Q000032:analysis*; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods* / Q000592:standards
chemical_list: D001789:Blood Group Antigens; D025942:Oligosaccharides, Branched-Chain; D019158:N-Acetylneuraminic Acid