Mapping site-specific protein N-glycosylations through liquid chromatography/mass spectrometry and targeted tandem mass spectrometry

摘要

Glycosylation is one of the most common posttranslational modifications (PTMs) of proteins, thecharacterization of which is commonly achieved through proteomic protocol, involving trypsin diges-tion followed by liquid chromatography/tandem mass spectrometry (LC/MS/MS). However, it is oftennot possible to characterize all glycopeptides in a complex sample because of the high complexity ofglycoproteomic samples, and the relative lower abundances of glycopeptides in comparison to theunmodified peptides. We present here a targeted MS/MS analysis approach, which utilizes a previouslydeveloped computational tool, GlyPID, to guide multiple experiments, thus permitting a completecharacterization of all N-glycosylation sites of glycoproteins present in a complex sample. We havetested our approach using model glycoproteins analyzed by high-resolution LTQ-FT MS. The resultsdemonstrate a potential use of our method for a high-throughput characterization of complex mixturesof glycosylated proteins.