How do I identify O-GlcNAc peptides by mass spectrometry after PTMScan®?

The PTMScan O-GlcNAc [GlcNAc-S/T] Motif Kit #95220 employs an antibody that will immunoprecipitate peptides with the native O-GlcNAc PTM on serine (S) or threonine (T) residues. To identify these peptides by mass spectrometry (MS), the fragmentation method most commonly employed is high energy collisional disassociation (HCD), or electron transfer dissociation (ETD). HCD fragmentation can produce the O-GlcNAc oxonium ion (+204.08 m/z); as well as oxonium ion fragments of m/z 186.07, 168.06 144.06, 138.05 and 126.05.

The ETD method of fragmentation has the advantage of not breaking the O-GlcNAc bond to the serine or threonine residue, improving the efficiency of localizing the PTM correctly on the parent peptide. See Ma and Hart Clinical Proteomics 2014, 11:8; http://www.clinicalproteomicsjournal.com/content/11/1/8.
 

Last updated: February 27, 2024