Oral Presentation 10th Australian Peptide Conference 2013

Captive, Doped and Boosted: Enhancing capabilities for glycopeptide characterization with ETD/CID through electrospray supercharging (#12)

Sawyen Ow 1
  1. Life Science Applications Manager Asia-Pacific & Japan, Bruker, Selangor, Malaysia

Although the analysis of glycosylation patterns in glycoproteins has been well established, parallel analysis to localize glycosylation sites as well as determining the peptide amino acid sequences are also paramount in reducing analysis time and improving data mining. The generally lower ionization efficiency of glycopeptides compared with non-glycosylated peptides during mass analysis coupled with the high micro-heterogeneity in glycan structures however, have made the analysis of N- and O-glycopeptides largely a challenging subject. More recently, the combination of collision-induced-dissociation (CID) and electron-transfer-dissociation (ETD) techniques has been shown to be highly complementary and provides a more comprehensive characterization of glycopeptides. However, confident use of ETD has often been hampered by the lower charge states and the significantly increased molecular weights of glycopeptides. Herein, the application of a new spray source set-up utilizing a solvent-doped sheath gas has the capability to not only augment charge states, but improve overall signal intensities during mass spectrometry analysis is presented. We apply this pilot investigation on a model glycoprotein and report on the overall performance increase. We also observed that supercharging appears most pronounced on glycopeptides with larger glycans and/or higher degrees of sialylation. Based on this methodology, we demonstrate its successful application on the analysis of both N- and O-linked glycopeptides.