Negative Electrospray, Ion Trap Multistage Mass Spectrometry of Synthetic Fragments of the O-PS of Vibrio Cholerae O:1

Abstract

Saccharides (mono through hexasaccharides) that mimic the terminal epitopes of O-antigens of Vibrio cholerae O:1, serotypes Ogawa and Inaba, were studied by electrospray ion trap (ESI IT) mass spectrometry (MS) in the negative mode. Anionized adducts are the characteristic ions formed by the capture of H(3)O(2)(-) under the condition of ESI MS analysis. The reactive species are produced by reaction of hydroxyl anions with the molecule of water. Thus the [M + H(3)O(2)](-) have the highest m/z value in the ESI IT negative mass spectra. After dissociation of adducts by loss of 2H(2)O the [M-H](-) ions are produced. The fragmentation pathways were confirmed by multistage measurements (MS(n)). The predominant pathway of fragmentation of the mono- and oligomers is the elimination of a molecule of alpha- hydroxy--gammabutyrolactone from the 4-(3-deoxy-L-glycero-tetronamido) group. The other characteristic pathway occurs by shortening the length of oligosaccharides. In this way, conversion of the Ogawa to Inaba fragments takes place under the conditions of measurement. Negative ESI MS/MS provided sufficient information about molecular mass, the number of saccharide residues, basic structure of saccharides, about the tetronamide part of the compounds investigated and allowed Ogawa and Inaba serotypes to be distinguished.

Negative Matrix-Assisted Laser Desorption/Ionization Time-of-Flight/Time-of-Flight Tandem Mass Spectrometry Fragmentation of Synthetic Analogs of the O-Specific Polysaccharide of Vibrio Cholerae O:1 in the Presence of Anionic Dopants

“…The elimination only takes place in the first step of the fragmentation. The secondary and tertiary ions of this kind are not present, which is in contrast to the ESI/IT negative mode fragmentation, 10 where the stepwise elimination of lactone molecules takes place. The MALDI-ToF/ToF-MS/MS spectra of all In and Og oligomers with the notation of fragments produced are summarized in the Table 1.…”

“…[9][10][11] A comparison of the MS spectra of the oligomers of Ogawa and Inaba types confirms that the leaving residue in the first step of the chain-shortening pathway is the terminal upstream mannose unit with the C(2) hydroxyl or methoxyl group. Formally, the chain shortening pathways resembled the Y (nomenclature introduced by Domon and Costello 27 ) fast atom bombardment fragmentation pathway of oligosaccharides.…”

“…Characteristic feature of the electrospray ionization ion trap (ESI/IT) negative fragmentation is stepwise elimination of the C-4 N-acyl groups in the form of α-hydroxy-γ-butyrolactone molecules. 10 The matrix-assisted laser desorption/ionization time-of-flight/ time-of-flight (MALDI-ToF/ToF) collision-induced dissociation mass spectrometry (CID-MS)was the next tested technique in the positive mode. 11 Characteristic of this fragmentation is the conjugated electron transfer in the terminal, upstream pyranoid cycle.…”

Fragmentation analysis of O-specific polysaccharide from bacteria Vibrio cholerae O139 by MALDI-TOF and LC/ESI-MS/MS

“…13 For fragmentation analysis of OSP of V. cholerae O1, negative matrix-assisted laser desorption ionization (MALDI)-time of flight (TOF)/TOF and positive and negative ESI-MS/ MS analyzes were used. 14,15,16 MALDI-TOF/TOF and ESI-MS/MS analyzes were also used for fragmentation analysis of bacterial LPSs, lipooligosaccharides and O-antigens of other bacteria, such as Neisseria meningitidis, Escherichia coli or Vibrio fischeri. [17][18][19][20] In this work, structural and fragmentation analyzes of the OSP and core part of LPS isolated from V. cholerae O139 were performed by i.)…”