title: Aspects of the sequencing of carbohydrates and oligonucleotides by matrix-assisted laser desorption/ionization post-source decay.
abstract: The possibility of structural elucidation of carbohydrates and oligonucleotides by matrix-assisted laser desorption/ionization followed by post-source decay (MALDI-PSD) is investigated. Spectra of both classes of compounds exhibit the better signal-to-noise ratios for the intact species in the negative-ion mode, but the most informative spectra for structural elucidation by PSD are obtained in the positive-ion mode. A novel fragmentation mode is demonstrated on a model sialylated complex type N-linked oligosaccharide. Prompt fragmentation in the positive-ion mode can remove the sialic acids at high laser irradiance if a suitable matrix is used. The remaining sugar backbone is then characterized by post-source decay. A modified oligonucleotide is analyzed with 3-hydroxypicolinic acid as the matrix and ammonium tartrate to displace sodium. Enough structural information is obtained to verify the modification.
authors.affiliation: Protein and Peptide Group, European Molecular Biology Laboratory, Heidelberg, Germany.
authors.forename: G
authors.initials: G
authors.lastname: Talbo
authors.forename: M
authors.initials: M
authors.lastname: Mann
mesh_terms: D008401:Gas Chromatography-Mass Spectrometry; D009841:Oligonucleotides / Q000032:analysis*; D017422:Sequence Analysis, DNA / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013644:Tartrates
chemical_list: D009841:Oligonucleotides; D013644:Tartrates; C029768:tartaric acid