A Novel Two-Stage Tandem Mass Spectrometry Approach and Scoring Scheme for the Identification of O-GlcNAc Modified Peptides

作者：Hahne Hannes; Kuster Bernhard^*

来源：Journal of the American Society for Mass Spectrometry, 2011, 22(5): 931-942.

DOI：10.1007/s13361-011-0107-y

• Tandem mass spectrometry
• O-GlcNAc
• Pulsed Q dissociation
• Electron-transfer dissociation

The modification of serine and threonine residues in proteins by a single N-acetylglucosamine (O-GlcNAc) residue is an emerging post-translational modification (PTM) with broad biological implications. However, the systematic or large-scale analysis of this PTM is hampered by several factors, including low stoichiometry and the lability of the O-glycosidic bond during tandem mass spectrometry. Using a library of 72 synthetic glycopeptides, we developed a two-stage tandem MS approach consisting of pulsed Q dissociation (PQD) for O-GlcNAc peptide detection and electron transfer dissociation (ETD) for identification and site localization. Based on a set of O-GlcNAc specific fragment ions, we further developed a score (OScore) that discriminates O-GlcNAc peptide spectra from spectra of unmodified peptides with 95% sensitivity and 999% specificity. Integrating the OScore into the two-stage LC-MS/MS approach detected O-GlcNAc peptides in the low fmol range and at 10-fold better sensitivity than a single data-dependent ETD tandem MS experiment.

• 出版日期2011-5