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Glycosidic intermediates identified in 1 H MR spectra of intact tumour cells may contribute to the clarification of aspects of glycosylation pathways
Author(s) -
Grande Sveva,
Palma Alessandra,
Luciani Anna Maria,
Rosi Antonella,
Guidoni Laura,
Viti Vincenza
Publication year - 2011
Publication title -
nmr in biomedicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.278
H-Index - 114
eISSN - 1099-1492
pISSN - 0952-3480
DOI - 10.1002/nbm.1557
Subject(s) - glycosylation , uridine , biochemistry , glycoprotein , chemistry , biosynthesis , nucleotide , nucleotide sugar , glycosidic bond , glutamine , glycolipid , galactosyltransferase , ammonium chloride , amino acid , rna , enzyme , gene , organic chemistry
The glycosylation process, through the addition of carbohydrates, is a major post‐translational modification of proteins and glycolipids. Proteins may be glycosylated in either the secretory pathway leading to N ‐linked or O ‐linked glycoproteins or as nucleocytoplasmic glycosylation that targets only single proteins involving a single β‐linked N ‐acetylglucosamine. In both cases, the key precursors are the uridine diphospho‐ N ‐acetylhexosamines synthesised by the hexosamine biosynthetic pathway. Furthermore, uridine diphospho‐ N ‐acetylglucosamine participates in the biosynthesis of sialic acid. In this work, we propose MRS for the detection of uridine diphospho‐ N ‐acetylhexosamines visible in high‐resolution MR spectra of intact cells from different human tumours. Signals from the nucleotide and amino sugar moieties, including amide signals observed for the first time in whole cells, are assigned, also taking advantage of spectral changes that follow cell treatment with ammonium chloride. Finally, parallel changes in uridine diphospho‐ N ‐acetylhexosamines and glutamine pools, observed after pH changes induced by ammonium chloride in the different tumour cell lines, may provide more details on the glycosylation processes. Copyright © 2010 John Wiley & Sons, Ltd.