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Molecular Beam Mass Spectrometry With Tunable Vacuum Ultraviolet VUV Synchrotron Radiation
Published on: October 30, 2012
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Ultraviolet Photodissociation Permits Comprehensive Characterization of
Amanda Helms1, Edwin E Escobar1,2, Saulius Vainauskas2
1Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States.
Analytical Chemistry
|June 8, 2023
Summary
Characterizing O-glycopeptides, including their sites and glycans, is challenging. A new strategy using O-glycoprotease IMPa and ultraviolet photodissociation (UVPD) successfully mapped multiple O-glycosites and glycans on complex glycoproteins.
Area of Science:
- Biochemistry
- Proteomics
- Glycoscience
Background:
- O-glycosite characterization is crucial but technically challenging, especially for multi-glycosylated peptides with heterogeneous glycan structures.
- Existing methods struggle with comprehensive analysis of O-glycans, including peptide identification, glycosite localization, and glycan mapping.
- Ultraviolet photodissociation (UVPD) shows promise for localizing multiple post-translational modifications and characterizing glycans.
Purpose of the Study:
- To develop and validate a strategy for complete O-glycopeptide characterization.
- To assess the efficacy of combining O-glycoprotease IMPa with HCD-triggered UVPD for analyzing complex glycoproteins.
- To compare the performance of UVPD with HCD and EThcD for O-glycosite localization and glycopeptide analysis.
Main Methods:
- Utilized O-glycoprotease IMPa for enzymatic digestion of glycoproteins.
- Employed HCD-triggered UVPD for fragmentation and analysis of glycopeptides.
- Analyzed three glycoproteins, including etanercept, to evaluate the combined approach.
Main Results:
- Successfully localized multiple adjacent or proximal O-glycosites on individual glycopeptides.
- Identified a novel O-glycosite at serine 218 (S218) on etanercept.
- Characterized nine distinct glycoforms from a multi-glycosylated peptide of etanercept.
- Compared UVPD performance against HCD and EThcD for O-glycosite localization and glycopeptide/glycan characterization.
Conclusions:
- The combined O-glycoprotease IMPa and HCD-triggered UVPD strategy enables comprehensive O-glycopeptide characterization.
- This approach overcomes challenges in analyzing multi-glycosylated peptides and heterogeneous glycan structures.
- UVPD offers a powerful alternative for O-glycosite localization and glycan analysis in glycoproteomics.
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