N-terminal protein characterization by mass spectrometry using combined microscale liquid and solid-phase...

Area of Science:

• Proteomics
• Analytical Chemistry
• Biochemistry

Background:

• Efficient isolation of N-terminal peptides is crucial for protein identification and characterization.
• Existing methods often face challenges with throughput, robustness, and simplicity.

Purpose of the Study:

• To develop a novel, robust, and high-throughput sample preparation method for selective N-terminal peptide isolation.
• To demonstrate the method's applicability to low picomole quantities of digested proteins.

Main Methods:

• Protection of protein thiols and amines, followed by trypsinization.
• Sequential modification of newly generated N-termini on reversed-phase supports.
• Reversible capture of internal and C-terminal peptides via covalent chromatography, leaving N-terminal peptides in solution.

Main Results:

• Successful isolation of N-terminal peptides from both in-solution and in-gel digested proteins at low picomole levels.
• Demonstrated selectivity in retrieving the N-terminal fragment from the affinity support.
• Optimization of serial modification steps for improved throughput and derivatization completeness.

Conclusions:

• The developed method offers a simple, robust, and high-throughput solution for N-terminal peptide enrichment.
• The technique is compatible with standard laboratory equipment and has potential for proteome-wide applications.