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Negative ion cid fragmentation of o-linked oligosaccharide aldoses—charge induced and charge remote fragmentation

Doohan, Roisin A.
; 
Hayes, Catherine A.
; 
Harhen, Brendan
; 
Karlsson, Niclas Göran
Repository DOI
Publication Date
2011-03-31
Keywords
glycomics, mass spectrometry, electrospray, o-linked oligosaccharides, liquid chromatography/mass spectrometry, electrospray mass-spectrometry, alkaline borohydride treatment, carbohydrate microarrays, sulfated oligosaccharides, part 1, glycoproteins, glycosylation, glycans, mucin
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Article
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Doohan, Roisin A. Hayes, Catherine A.; Harhen, Brendan; Karlsson, Niclas Göran (2011). Negative ion cid fragmentation of o-linked oligosaccharide aldoses—charge induced and charge remote fragmentation. Journal of The American Society for Mass Spectrometry 22 (6), 1052-1062
Abstract
Collision induced dissociation (CID) fragmentation was compared between reducing and reduced sulfated, sialylated, and neutral O-linked oligosaccharides. It was found that fragmentation of the [M - H](-) ions of aldoses with acidic residues gave unique Z-fragmentation of the reducing end GalNAc containing the acidic C-6 branch, where the entire C-3 branch was lost. This fragmentation pathway, which is not seen in the alditols, showed that the process involved charge remote fragmentation catalyzed by a reducing end acidic anomeric proton. With structures containing sialic acid on both the C-3 and C-6 branch, the [M - H](-) ions were dominated by the loss of sialic acid. This fragmentation pathway was also pronounced in the [M - 2H](2-) ions revealing both the C-6 Z-fragment plus its complementary C-3 C-fragment in addition to glycosidic and cross ring fragmentation. This generation of the Z/C-fragment pairs from GalNAc showed that the charges were not participating in their generation. Fragmentation of neutral aldoses showed pronounced Z-fragmentation believed to be generated by proton migration from the C-6 branch to the negatively charged GalNAc residue followed by charge remote fragmentation similar to the acidic oligosaccharides. In addition, A-type fragments generated by charge induced fragmentation of neutral oligosaccharides were observed when the charge migrated from C-1 of the GalNAc to the GlcNAc residue followed by rearrangement to accommodate the (0,2)A-fragmentation. LC-MS also showed that O-linked aldoses existed as interchangeable alpha/beta pyranose anomers, in addition to a third isomer (25% of the total free aldose) believed to be the furanose form.
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Publisher
Springer Nature
Publisher DOI
10.1007/s13361-011-0102-3
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Attribution-NonCommercial-NoDerivs 3.0 Ireland
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Externally hosted open access publications with University of Galway authors (2)