Exploring Gas-Phase MS Methodologies for Structural Elucidation of Branched N-Glycan Isomers

• DOI: 10.1021/acs.analchem.2c02019
• Publication Date: 2022-07-14T13:22:17Z
• Authors: Irina Oganesyan; Joanna Hajduk; Julian A. Harrison; Adrien Marchand; Martin F. Czar; Renato Zenobi
• Keywords: Conformational isomerism; Structural isomer; Fragmentation; Cis–trans isomerism; Ion-mobility spectrometry; Hydrogen–deuterium exchange; Collision-induced dissociation

Structural isomers of N-glycans that are identical in mass and atomic composition provide a great challenge to conventional spectrometry (MS). This study employs additional dimensions structural elucidation including ion mobility (IM) spectroscopy coupled hydrogen/deuterium exchange (HDX) electron capture dissociation (ECD) characterize three main A2 their conformers. A series IM–MS experiments were able separate the low abundance linkage-based (α1-3 α1-6 for A2G1). HDX–IM–MS data indicated presence multiple gas-phase structures each N-glycan A2G1. Identification A2G1 by collision cross section was complicated due preferential collapse sugars gas phase, but it possible further ECD fragmentation. The cyclic IM–ECD approach capable assigning identifying isomer its IM peak. Two unique cross-ring fragments identified isomer: m/z = 624.21 462.16 α1-3. Based on these key fragments, first peak, indicating more compact conformation, assigned α1-3 second extended conformer, α1-6.