1. EThcD spectrum of m/z (3+), acquired on a Orbitrap Fusion Lumos Tribrid mass spectrometer (Thermo Fisher Scientific) (at NCE = 15%).
EThcD spectrum of m/z (3+), acquired on a Orbitrap Fusion Lumos Tribrid mass spectrometer (Thermo Fisher Scientific) (at NCE = 15%). The modified sequence was identified from these data as AVAVTLQSH [342–350] of human YIPF3 protein (Uniprot ID: Q9GZM5). The glycan is most likely the disialo mucin-type core-1 structure, one of the glycans listed as potential variable modifications of Ser and Thr residues. Extensive HexNAc fragmentation was not observed, thus, the GalNAc's identity cannot be established unambiguously from these data. In the reducing end fragment ion Y2SA, the sialic acid could be linked either to the GalNAc or the Gal. The modification site was identified as Thr-5, fragments printed in red are unique to this positional variant. No fragment ions indicated modification on the Ser residue. The precursor ion and its charge-reduced versions are labeled as “pr.”
Zsuzsanna Darula, and Katalin F. Medzihradszky Mol Cell Proteomics 2018;17:2-17
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