Open AccessPrecision Mapping of O-Linked N-Acetylglucosamine Sites in Proteins Using Ultraviolet Photodissociation Mass Spectrometry
Author(s) -
Edwin E. Escobar,
D.T. King,
Jesús E Serrano-Negrón,
Matthew G. Alteen,
David J. Vocadlo,
Jennifer S. Brodbelt
Publication year - 2020
Publication title -
journal of the american chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.115
H-Index - 612
eISSN - 1520-5126
pISSN - 0002-7863
DOI - 10.1021/jacs.0c04710
Subject(s) - chemistry , photodissociation , mass spectrometry , tandem mass spectrometry , dissociation (chemistry) , fragmentation (computing) , electron capture dissociation , infrared multiphoton dissociation , proteome , ultraviolet , ion , glycosidic bond , peptide , biophysics , photochemistry , biochemistry , chromatography , organic chemistry , physics , computer science , biology , enzyme , operating system , quantum mechanics
Despite its central importance as a regulator of cellular physiology, identification and precise mapping of O-linked N -acetylglucosamine (O-GlcNAc) post-translational modification (PTM) sites in proteins by mass spectrometry (MS) remains a considerable technical challenge. This is due in part to cleavage of the glycosidic bond occurring prior to the peptide backbone during collisionally activated dissociation (CAD), which leads to generation of characteristic oxocarbenium ions and impairs glycosite localization. Herein, we leverage CAD-induced oxocarbenium ion generation to trigger ultraviolet photodissociation (UVPD), an alternate high-energy deposition method that offers extensive fragmentation of peptides while leaving the glycosite intact. Upon activation using UV laser pulses, efficient photodissociation of glycopeptides is achieved with production of multiple sequence ions that enable robust and precise localization of O-GlcNAc sites. Application of this method to tryptic peptides originating from O-GlcNAcylated proteins TAB1 and Polyhomeotic confirmed previously reported O-GlcNAc sites in TAB1 (S395 and S396) and uncovered new sites within both proteins. We expect this strategy will complement existing MS/MS methods and be broadly useful for mapping O-GlcNAcylated residues of both proteins and proteomes.