Structural characterization and analysis of different epimers of neutral glycosphingolipid LcGg4 by ion mobility spectrometry-mass spectrometry.

Abstract

LcGg4, a neutral glycosphingolipid (GSL) and cancer antigen, its epimers GalNAc-LcGg4 and GlcNAc-LcGg4, and three lipid forms of GalNAc-LcGg4 were studied by mass spectrometry (MS). It was found that different forms of GalNAc-LcGg4 carrying homologous (d16:1/18:0) and (d18:1/18:0) lipids were easily separated and identified using liquid chromatography (LC)-MS. In addition, like gangliosides, homologous lipid forms of GalNAc-LcGg4 showed the same fragmentation pattern, except for a uniform shift of their glycolipid product ions by a certain m/z number determined by the varied lipid structure. It was also disclosed that LcGg4 and its epimers GalNAc-LcGg4 and GlcNAc-LcGg4, which are different only in the C4-configuration of their non-reducing end sugar residues, gave the same MS/MS product ions in similar relative intensities, as well as the same LC retention time, suggesting the challenge to differentiate epimeric GSLs by LC-MS. However, ion mobility spectrometry (IMS)-MS was able to efficiently separate and distinguish these epimers. This study has demonstrated the promise of IMS-MS for isomeric GSL characterization and the IMS-MS and LC-MS/MS combination for natural GSL analysis.

• Authors: Tianqi Gao, Aneirin A Lott, Fanran Huang, Rajendra Rohokale, Qingjiang Li, Hernando J Olivos, Sixue Chen, Zhongwu Guo
• Journal: The Analyst (Analyst) Vol. 147 Issue 13 Pg. 3101-3108 (Jun 27 2022) ISSN: 1364-5528 [Electronic] England
• PMID: 35695136 (Publication Type: Journal Article)

Chemical References

• Gangliosides
• Neutral Glycosphingolipids
• lactogangliotetraosylceramide

Topics

• Chromatography, Liquid (methods)
• Gangliosides
• Ion Mobility Spectrometry
• Neutral Glycosphingolipids
• Tandem Mass Spectrometry