Low Collision Energy Fragmentation in Structure-Specific Glycoproteomics Analysis

Anal Chem. 2020 Jun 16;92(12):8262-8267. doi: 10.1021/acs.analchem.0c00519. Epub 2020 Jun 4.

Abstract

Glycosylation is a major post-translational modification of proteins that regulates many biological processes including protein folding, structure stability, receptor activation, and immune responses. The glycans attached to proteins represent an important determinant of the protein interaction-specificity and maintain the 3D structure of proteins. Mass spectrometry (MS) is one of the most efficient tools used in the current studies of glycoproteins and structure of their glycoforms. Collision energy (CE) is a crucial instrument parameter that can be exploited to improve structural resolution because different linkages of glycan units show different stabilities under CID/HCD fragmentation. Here we report the utility of CE modulation for qualitative and quantitative analysis of site- and structure-specific glycoforms of proteins. Using CE modulation, we were able to break selectively specific glycan linkages on intact glycopeptides and get, to some degree, structure-specific mass spectrometric signals. Structure- and CE-specific oxonium ions provide sufficient information for the resolution of outer arm structure motifs with recognized biological functions. The complementary Y-ions, generated under optimized low CE (soft) conditions, provide additional structural information including features specific to the chitobiose core. This methodology of multiple CE fragmentation without merging spectral information can significantly improve confidence of glycopeptide identification and structural resolution by providing additional information to the established glycopeptide-search algorithms and tools.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Chromatography, Liquid
  • Energy Metabolism
  • Glycopeptides / analysis*
  • Glycopeptides / chemical synthesis
  • Glycopeptides / metabolism
  • Glycoproteins / analysis*
  • Glycoproteins / metabolism
  • Glycosylation
  • Humans
  • Proteomics*
  • Recombinant Proteins / analysis
  • Recombinant Proteins / metabolism
  • Tandem Mass Spectrometry

Substances

  • Glycopeptides
  • Glycoproteins
  • Recombinant Proteins