title: Positive-ion fragmentation in matrix-assisted laser desorption/ionization tandem time of flight mass spectrometry of synthetic analogs of the O-specific polysaccharide of Vibrio cholerae O:1.
abstract: Saccharides (mono- to hexamers) that mimic the terminal epitopes of O-antigens of Vibrio cholerae O:1, serotypes Ogawa and Inaba have been studied by matrix-assisted laser desorption/ionization tandem time-of-flight (MALDI ToF/ToF) mass spectrometry (MS). Cationized adducts are the characteristic ions formed through the capture of sodium or potassium cations under MALDI MS conditions. Three characteristic pathways dominate in the fragmentation of model substances under MALDI ToF/ToF collision-induced dissociation MS/MS conditions of measurement. The first is the elimination which shortens the length of the oligosaccharide. In this way, conversion of the Ogawa to Inaba fragments takes place under the conditions of measurement. In the second, the conjugated transfer of electrons in the upstream unit of oligosaccharides takes place. The third route brings about the elimination of one alpha-hydroxy-gamma-butyrolactone molecule from the 4-(3-deoxy-L-glycero-tetronamido) group. The MALDI ToF/ToF MS/MS provided sufficient information about molecular mass, the number of saccharide residues, the structure of saccharides, the C(4)- amide of 3-deoxy-L-glycero-tetronic acid (DGT) of the compounds investigated, and allows to distinguish between Ogawa and Inaba serotypes.
authors.affiliation: Institute of Chemistry, Slovak Academy of Sciences, Dúbravská cesta 9, 845 38 Bratislava, Slovakia. chemvkov@savba.sk
authors.forename: Vladimír
authors.initials: V
authors.lastname: Kovácik
authors.forename: Slávka
authors.initials: S
authors.lastname: Bekesová
authors.forename: Vladimír
authors.initials: V
authors.lastname: Pätoprstý
authors.forename: Pavel
authors.initials: P
authors.lastname: Rehulka
authors.forename: Josef
authors.initials: J
authors.lastname: Chmelík
authors.forename: Pavol
authors.initials: P
authors.lastname: Kovác
mesh_terms: D000596:Amino Acids / Q000737:chemistry; D002240:Carbohydrate Sequence; D007202:Indicators and Reagents; D008969:Molecular Sequence Data; D011134:Polysaccharides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D053719:Tandem Mass Spectrometry; D041241:Vibrio cholerae O1 / Q000737:chemistry*
chemical_list: D000596:Amino Acids; D007202:Indicators and Reagents; D011134:Polysaccharides