Fig 6. Analysis of the N-glycosylation of the heavy chain by mass spectrometry.

A) MS spectrum of the glycopeptide from the heavy chain of the secreted and ER-retained antibodies produced in P. tricornutum. B) MS/MS spectrum of the glycopeptide bearing a Man–9 structure ([M+2H]²⁺ precursor ion at m/z 1527.57). Fragment ions were annotated using Domon and Costello nomenclature [37]. The asterisks indicate multiple fragment ions that have been identified but not annotated on the spectrum. Glycan structures are annotated with their proposed carbohydrate structure according to the symbolic nomenclature from the Consortium for Functional Glycomics [38]. Black square: N-acetylglucosamine; green circle: mannose.