Comparison of fragmentation modes for the structural determination of complex oligosaccharides ionized by matrix-assisted laser desorption/ionization mass spectrometry.
Fragment ions from underivatized N-linked oligosaccharides ionized by matrix-assisted laser desorption/ionization mass spectrometry were obtained by spontaneous fragmentation on a magnetic sector mass spectrometer, by post-source decay (PSD) on a reflectron time-of-flight (TOF) instrument and by collision-induced dissociation on a magnetic sector instrument fitted with an orthagonal-TOF analyser. Spontaneous fragmentation on the magnetic sector instrument produced ions mainly by glycosidic cleavage together with two abundant ions formed by cross-ring cleavage of the reducing-terminal residue. The PSD spectra were similar, the majority of ions being formed by glycosidic cleavage. Internal fragment ions were abundant. High-energy collision-induced dissociation spectra recorded with the orthagonal-TOF analyser, differed considerably from the other types of spectra, particularly in the appearance of major fragment ions produced by cross-ring cleavages of most of the constituent monosaccharide residues. These ions allowed much sequence and branching information to be obtained from the oligosaccharide.
Harvey
D J
DJ
Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, UK.
Naven
T J
TJ
Küster
B
B
Bateman
R H
RH
Green
M R
MR
Critchley
G
G
D002240:Carbohydrate Sequence; D005697:Galactosides / Q000032:analysis; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D008969:Molecular Sequence Data; D009844:Oligosaccharides / Q000032:analysis*
D005697:Galactosides; D009844:Oligosaccharides