Generating cysteine-trypsin cleavage sites with 2-chloroacetamidine capping

Area of Science:

• Proteomics
• Mass Spectrometry
• Biochemistry

Background:

• Proteolytic digestion is crucial for mass spectrometry-based proteomics.
• Trypsin typically cleaves at arginine and lysine residues.
• Cysteine residues pose challenges for standard proteomic workflows due to their unique reactivity.

Purpose of the Study:

• To develop a novel strategy for enhancing proteomic analysis of cysteine-containing peptides.
• To improve the identification of missense variants using mass spectrometry.
• To leverage electrophilic arginine mimetics for targeted proteolysis.

Main Methods:

• Utilized 2-chloroacetamidine (CAM), an electrophilic arginine mimetic, to modify cysteine residues.
• Enabled trypsin-mediated proteolysis adjacent to modified cysteine residues.
• Performed proteogenomic analysis with a two-stage false discovery rate (FDR) search.

Main Results:

• >50% enhanced coverage of cysteine-containing peptides was achieved.
• Significantly improved detection of missense variants compared to established methods.
• Demonstrated the utility of the CAM-capping strategy in complex proteomic samples.

Conclusions:

• The CAM-capping strategy offers a powerful approach to overcome limitations in cysteine peptide analysis.
• This method enhances proteogenomic coverage and variant detection.
• CAM represents a valuable tool for advancing mass spectrometry-based proteomics.