Title : In-depth analysis of site-specific N-glycosylation in
vitronectin from human plasma by tandem mass spectrometry with immunoprecipitation
Abstract :
- The characterization of site-specific microheterogeneity in glycoprotein is very important for understanding cell biology and disease processes
- Vitronectin is well known to be a multifunctional glycoprotein in the blood and the extracellular matrix, which is related to hepatocellular carcinoma (HCC)
- Here, we systematically analyzed the site-specific N-glycopeptides of vitronectin in human plasma by tandem mass spectrometry combined with immunoprecipitation and hydrophilic interaction liquid chromatography (HILIC) enrichment
- Vitronectin was purified with immunoprecipitation by monoclonal antibody from plasma and digested to tryptic N-glycopeptides
- Then, enrichment with HILIC materials was used and followed by analysis with nano-LC/MS/MS
- The sequences of N-glycopeptides were identified from the mass spectra by high-energy C-trap dissociation ( HCD ) and collision-induced dissociation (CID)
- In HCD mode, oxonium ions were used for recognizing glycopeptides and y ions for sequencing the peptide backbone
- In CID mode, Y ions were used for characterizing their glycoforms
- As a result, a total of 17 site-specific N-glycopeptides were completely identified in all of the three N-glycosylation sites of vitronectin in human plasma, including 12 N-glycopeptides first reported
- Finally , we specifically found that three hybrid and four complex glycopeptides of triantennary forms with outer fucosylation increased in HCC human plasma