Automatically Full Glycan Structural Determination with Logically Derived Sequence Tandem Mass Spectrometry

Abstract

Here we show the full structures of glycans, including diastereomers and anomericity of each monosaccharide and linkage position of each glycosidic bond, can be determined using tandem mass spectrometry guided by a logically derived sequence (LODES). This new method provides de novo oligosaccharide structural identifications with high sensitivity and was applied to automatically in situ structural determination of the oligosaccharides eluted by high performance liquid chromatography. We showed that the structure of a given trisaccharide from trisaccharide mixture and bovine milk were determined from near three thousand isomers by using six to seven logically selected CID spectra. The entire procedure of mass spectrum measurement guided by LODES can be programmed in computer for automatically full glycan structural identification, a goal that remains a great challenge in glycan analysis.

Identification of novel high mannose N-glycan isomers undescribed by current multicellular eukaryotic biosynthetic pathways

“…The CID sequences in LODES were derived from carbohydrate dissociation mechanisms [42][43][44][45] . LODES enables us to determine the D, E, F, and G, according to the dissociation mechanisms of hexose [27][28][29][30][31][41][42][43] .…”

“…We recently developed a mass spectrometry method, namely logically derived sequence (LODES) tandem mass spectrometry (MS n ), for oligosaccharide structural determination [27][28][29][30][31][32][33][34] . LODES/MS n does not depends on the mass spectrum database of oligosaccharides or N-glycan standards, thus LODES/MS n is particularly useful for the structural determination of the newly discovered N-glycans.…”