Figure 2 | Scientific Reports

Figure 2

From: Topological N-glycosylation and site-specific N-glycan sulfation of influenza proteins in the highly expressed H1N1 candidate vaccines

Figure 2

The structural N-glycan analyses of the tryptic neuraminidase peptide 144–152 isolated from the influenza vaccine NIBRG-121xp by LC MS/MS with high-resolution Orbitrap Fusion mass spectrometry. (A) MS spectrum of the peptide profile containing sulfated and bisected GlcNAc complex-type N-glycan forms. (B) MS/MS spectrum of the triply charged ion at m/z 1100.0963 (3 + ). The low energy collision-induced dissociation (CID) of the precursor ion displayed not only the consecutive losses of neutral saccharides from the glycan structure, as well as a chemical group loss at either 79.9550 Da or 79.9562 Da between the two pairs of doubly charged fragment ions. The accurate mass measurements identified the element composition of 79.9556 ± 0.0006 Da as being derived from a sulfate group (SO3, calculated mass: 79.9568 Da), and MS/MS analysis defined the site of monosulfate group at the terminal residue of either Gal or GlcNAc (or the isobaric GalNAc) on the branched N-glycan side chain.

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