Characterization of lipid-linked oligosaccharides by mass spectrometry.

N- Glycosylation of proteins is recognized as one of the most common post-translational modifications. Until recently it was believed that N-glycosylation occurred exclusively in eukaryotes until the discovery of the general protein glycosylation pathway (Pgl) in Campylobacter jejuni. We have developed a new glycomics strategy based on lectin-affinity capture of lipid-linked oligosaccharides (LLOs) coupled to capillary electrophoresis mass spectrometry. The LLO intermediates of the C. jejuni Pgl pathway were used to validate the methodology and to better characterize the bacterial model system for protein N-glycosylation. This method provides a rapid, non-radioactive approach for the characterization of intermediates in polysaccharide biosynthesis and is a useful tool for glycoengineering efforts in bacteria.