Figure 2.

Representative of MS/MS spectra for identification of N-linked glycopeptides using HCD spectral-aligning strategy. (A) MS/MS spectrum of deglycosylated peptide SVD²⁷⁶FTDNAK provided the information on experimentally identified b- and y-ions. (B) MS/MS spectrum of glycopeptide with matched pattern of b- and y-ions to that of deglycosylated peptide was identified. Additional b-, y-, and Y-ions facilitate identification of the glycopeptide SVN²⁷⁶FTDNAK with Man₇GlcNAc₂, which was used as a spectral template to identify glycopeptides with the same peptide backbone but different glycan Man₅GlcNAc₄ in (C).