Capturing site-specific heterogeneity with large-scale N-glycoproteome analysis

Area of Science:

• Biochemistry
• Proteomics
• Glycobiology

Background:

• Protein glycosylation is a critical post-translational modification with complex, poorly understood heterogeneity.
• Thousands of glycan structures contribute to potential site-specific variations, limiting biological insights.
• Existing analytical methods hinder large-scale analysis of intact glycopeptides.

Purpose of the Study:

• To develop and apply large-scale glycopeptide profiling methods for characterizing N-glycoproteome site-specific microheterogeneity.
• To investigate the biological implications of N-glycosylation heterogeneity in complex biological systems.
• To establish novel visualization tools for intact glycopeptide analysis.

Main Methods:

• Utilized activated ion electron transfer dissociation (AI-ETD) for enhanced glycopeptide fragmentation.
• Performed large-scale glycopeptide profiling on mouse brain tissue.
• Characterized over 1,545 N-glycosites and >5,600 unique N-glycopeptides.

Main Results:

• Successfully captured N-glycoproteome site-specific microheterogeneity using AI-ETD.
• Revealed differences in N-glycosylation profiles across subcellular regions and structural domains.
• Demonstrated diverse forms of N-glycosite heterogeneity, even on the same protein.

Conclusions:

• AI-ETD-enabled glycopeptide profiling is a powerful approach for dissecting N-glycosylation heterogeneity.
• N-glycosylation exhibits significant site-specific and domain-specific variations with biological relevance.
• Developed novel visualizations to aid future intact glycopeptide analysis.