An efficient approach based on basic strong cation exchange chromatography for enriching methylated peptides with...

Area of Science:

• Biochemistry
• Proteomics
• Post-translational Modifications

Background:

• Protein methylation is a crucial post-translational modification involved in numerous biological processes.
• Current antibody-based enrichment methods for methylproteomics lack a pan-specific antibody for all lysine and arginine methylation forms.
• Advancing methylproteomics requires novel enrichment strategies for comprehensive analysis.

Purpose of the Study:

• To develop an effective method for enriching methylated peptides for large-scale methylproteomics analysis.
• To overcome the limitations of existing antibody-based enrichment techniques.
• To facilitate the study of biological processes mediated by protein methylation.

Main Methods:

• Development of an online basic strong cation exchange chromatography method for methylated peptide enrichment.
• Preparation of protein digests using two complementary methods: direct multiple enzyme digestion and carboxylic amidation followed by multiple enzyme digestion.
• Analysis of enriched peptides using liquid chromatography-tandem mass spectrometry (LC-MS/MS).

Main Results:

• The direct multiple enzyme digestion method yielded the majority of identifications after enrichment.
• Achieved an enrichment specificity of up to 28.5% for methylated peptides.
• Identified 445 methylation forms across 376 unique methylation sites on 194 proteins in a single LC-MS/MS run with 100 μg of digests.

Conclusions:

• The developed online basic strong cation exchange chromatography method effectively enriches methylated peptides.
• This method offers a promising approach for large-scale methylproteomics and studying protein methylation-mediated biological processes.
• The technique provides a valuable tool for advancing research in the field of post-translational modifications.