title: Structural analysis of permethylated oligosaccharides using electrospray ionization quadrupole time-of-flight tandem mass spectrometry and deutero-reduction.
abstract: Deutero-reduced permethylated oligosaccharides were analyzed by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS) using a hybrid quadrupole orthogonal acceleration time-of-flight mass spectrometer, fitted with a nanoflow ESI source. Under these ionization conditions such derivatives preferentially form sodiated molecular species in addition to protonated molecular species. Under collision-induced dissociation, protonated and sodiated molecular species yield simple and predictable fragment mass spectra. A systematic study was conducted on a series of deutero-reduced permethylated glycans to allow rationalization of the fragmentation processes. MS/MS spectra were characterized by fragments resulting from the cleavage of glycosidic bonds. These fragments originating from both the reducing and the non-reducing ends of the glycan yield information on sequence and branching. Furthermore, the substituent 3-linked to a HexNAc unit was readily eliminated. Special attention was devoted to a systematic study of fucosylated glycans. The fucosylated deutero-reduced permethylated glycans were submitted to an acidic hydrolysis, releasing specifically the fucosyl residues. The nascent free hydroxyl groups were subsequently CD3-labelled in order to determine the positions initially bearing the fucosyl residues along the oligosaccharide backbone. This methodology was finally applied to characterize a glycan pool enzymatically released from glycoproteins. The present data show that structural elucidation can be achieved at the 50 fmol level.
authors.affiliation: Unité Mixte de Recherche CNRS/USTL 8576, Glycobiologie Structurale et Fonctionnelle, IFR 118, Université des Sciences et Technologies de Lille 1, 59655 Villeneuve d'Ascq Cedex, France. willy.morelle@univ-lillel.fr
authors.forename: Willy
authors.initials: W
authors.lastname: Morelle
authors.forename: Valegh
authors.initials: V
authors.lastname: Faid
authors.forename: Jean-Claude
authors.initials: JC
authors.lastname: Michalski
mesh_terms: D003903:Deuterium / Q000737:chemistry; D008745:Methylation; D008832:Microchemistry / Q000379:methods*; D008968:Molecular Conformation; D009844:Oligosaccharides / Q000032:analysis* / Q000737:chemistry*; D010084:Oxidation-Reduction; D011134:Polysaccharides / Q000032:analysis / Q000737:chemistry; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D009844:Oligosaccharides; D011134:Polysaccharides; D003903:Deuterium