A platform for the structural characterization of glycans enzymatically released from glycosphingolipids extracted from tissue and cells

Merrina Anugraham, Arun Vijay Everest-Dass, Francis Jacob, Nicolle H. Packer*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

19 Citations (Scopus)

Abstract

Rationale Glycosphingolipids (GSLs) constitute a highly diverse class of glyco-conjugates which are involved in many aspects of cell membrane function and disease. The isolation, detection and structural characterization of the carbohydrate (glycan) component of GSLs are particularly challenging given their structural heterogeneity and thus rely on the development of sensitive, analytical technologies. Methods Neutral and acidic GSL standards were immobilized onto polyvinylidene difluoride (PVDF) membranes and glycans were enzymatically released using endoglycoceramidase II (EGCase II), separated by porous graphitized carbon (PGC) liquid chromatography and structurally characterized by negative ion mode electrospray ionization tandem mass spectrometry (PGC-LC/ESI-MS/MS). This approach was then employed for GSLs isolated from 100 mg of serous and endometrioid cancer tissue and from cell line (107 cells) samples. Results Glycans were released from GSL standards comprising of ganglio-, asialo-ganglio- and the relatively resistant globo-series glycans, using as little as 1 mU of enzyme and 2 μg of GSL. The platform of analysis was then applied to GSLs isolated from tissue and cell line samples and the released isomeric and isobaric glycan structures were chromatographically resolved on PGC and characterized by comparison with the MS2 fragment ion spectra of the glycan standards and by application of known structural MS2 fragment ions. This approach identified several (neo-)lacto-, globo- and ganglio-series glycans and facilitated the discrimination of isomeric structures containing Lewis A, H type 1 and type 2 blood group antigens and sialyl-tetraosylceramides. Conclusion We describe a relatively simple, detergent-free, enzymatic release of glycans from PVDF-immobilized GSLs, followed by the detailed structural analysis afforded by PGC-LC-ESI-MS/MS, to offer a versatile method for the analysis of tumour and cell-derived GSL-glycans. The method uses the potential of MS2 fragmentation in negative ion ESI mode to characterize, in detail, the biologically relevant glycan structures derived from GSLs.

Original languageEnglish
Pages (from-to)545-561
Number of pages17
JournalRapid Communications in Mass Spectrometry
Volume29
Issue number7
DOIs
Publication statusPublished - 15 Apr 2015

Fingerprint Dive into the research topics of 'A platform for the structural characterization of glycans enzymatically released from glycosphingolipids extracted from tissue and cells'. Together they form a unique fingerprint.

Cite this