title: Assignment of saccharide identities through analysis of oxonium ion fragmentation profiles in LC-MS/MS of glycopeptides.
abstract: Protein glycosylation plays critical roles in the regulation of diverse biological processes, and determination of glycan structure-function relationships is important to better understand these events. However, characterization of glycan and glycopeptide structural isomers remains challenging and often relies on biosynthetic pathways being conserved. In glycoproteomic analysis with liquid chromatography-tandem mass spectrometry (LC-MS/MS) using collision-induced dissociation (CID), saccharide oxonium ions containing N-acetylhexosamine (HexNAc) residues are prominent. Through analysis of beam-type CID spectra and ion trap CID spectra of synthetic and natively derived N- and O-glycopeptides, we found that the fragmentation patterns of oxonium ions characteristically differ between glycopeptides terminally substituted with GalNAcα1-O-, GlcNAcβ1-O-, Galβ3GalNAcα1-O-, Galβ4GlcNAcβ-O-, and Galβ3GlcNAcβ-O- structures. The difference in the oxonium ion fragmentation profiles of such glycopeptides may thus be used to distinguish among these glycan structures and could be of importance in LC-MS/MS-based glycoproteomic studies.
authors.affiliation: Department of Clinical Chemistry and Transfusion Medicine, Institute of Biomedicine, ‡Department of Neurochemistry, Institute of Neuroscience and Physiology, University of Gothenburg , SE-41345 Gothenburg, Sweden.
authors.forename: Adnan
authors.initials: A
authors.lastname: Halim
authors.forename: Ulrika
authors.initials: U
authors.lastname: Westerlind
authors.forename: Christian
authors.initials: C
authors.lastname: Pett
authors.forename: Manuel
authors.initials: M
authors.lastname: Schorlemer
authors.forename: Ulla
authors.initials: U
authors.lastname: Rüetschi
authors.forename: Gunnar
authors.initials: G
authors.lastname: Brinkmalm
authors.forename: Carina
authors.initials: C
authors.lastname: Sihlbom
authors.forename: Johan
authors.initials: J
authors.lastname: Lengqvist
authors.forename: Göran
authors.initials: G
authors.lastname: Larson
authors.forename: Jonas
authors.initials: J
authors.lastname: Nilsson
mesh_terms: D000595:Amino Acid Sequence; D002240:Carbohydrate Sequence; D002853:Chromatography, Liquid / Q000379:methods*; D006020:Glycopeptides / Q000032:analysis / Q000378:metabolism*; D006031:Glycosylation; D008969:Molecular Sequence Data; D015394:Molecular Structure; D009844:Oligosaccharides / Q000737:chemistry / Q000378:metabolism*; D009861:Onium Compounds / Q000032:analysis / Q000378:metabolism*; D011134:Polysaccharides / Q000737:chemistry / Q000378:metabolism; D020543:Proteome / Q000032:analysis / Q000378:metabolism; D040901:Proteomics / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D006020:Glycopeptides; D009844:Oligosaccharides; D009861:Onium Compounds; D011134:Polysaccharides; D020543:Proteome; C027727:hydronium ion
keywords: LC−MS/MS; O-glycosylation; glycopeptide; glycoproteomics; oxonium ion