Tandem mass spectrum of hemagglutinin glycopeptide precursor ion
1013.7474 [M + 3H]3+, identified as NGSYPNLSK-[5,4,1,1,0].
Glycopeptide identifier is listed as peptide-[a,b,c,d,e], where a
= number of hexoses; b = number of N-acetylhexosamines;
c = number of deoxyhexoses; d = number of N-acetylneuraminic
acids; e = number of N-glycolylneuraminic acids.