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. 2016 Mar 14;2(5):313–321. doi: 10.1021/acsinfecdis.6b00026

Figure 3.

Figure 3

De novo sequencing via wild card search. Byonic matched the pictured mass spectrum to MNSLQAK{+189.026}DTGIYYC[+57.021]GR, where { } indicates a wild card (unidentified) mass delta and [ ] indicates a known modification, in this case cysteine alkylation. The peak at 204.086 is the oxonium ion for HexNAc, the nearly universal mark of a glycopeptide. Manual analysis quickly corrected the peptide to MNSLQAN[+203.079]DTGIYYC[+57.021]GR, explaining the peaks at 1218.525, 1289.556, and 1418.607 as ∼y10, ∼y11, and ∼y12 (iso1) with ∼ indicating loss of the glycan.