Chemical-Mediated Digestion: An Alternative Realm for Middle-down Proteomics?

Area of Science:

• Proteomics
• Analytical Chemistry
• Biochemistry

Background:

• Bottom-up proteomics typically yields small peptides (0.6-3 kDa) by targeting lysine and arginine residues.
• Advancements in mass spectrometry (MS) enable analysis of longer peptides, driving the development of middle-down proteomics (MDP).
• Generating peptides in the 3-15 kDa range is crucial for MDP, but suitable cleavage agents are needed.

Purpose of the Study:

• To investigate chemical agents for generating 3-15 kDa peptides suitable for middle-down proteomics.
• To evaluate the performance of chemical cleavage agents targeting rare amino acids like methionine, tryptophan, and cysteine.

Main Methods:

• Evaluated chemical agents CNBr, BNPS-Skatole, and NTCB for their ability to cleave proteins at specific rare amino acid residues.
• Assessed digestion reproducibility, peptide size distribution, and side reactions for each agent.
• Focused on NTCB for its potential in middle-down proteomics workflows.

Main Results:

• CNBr, BNPS-Skatole, and NTCB were tested as potential agents for middle-down proteomics (MDP) grade proteolysis.
• Performance metrics including digestion reproducibility, peptide size distribution, and side reactions were analyzed.
• The NTCB-based workflow demonstrated particularly attractive performance for generating longer peptides.

Conclusions:

• Chemical cleavage agents targeting rare amino acids are viable for generating peptides in the 3-15 kDa range for MDP.
• NTCB shows significant promise as a cleaving agent for advancing middle-down proteomics workflows.
• Further development of NTCB-based MDP protocols is warranted.