Broad coverage identification of multiple proteolytic cleavage site sequences in complex high molecular weight...

Area of Science:

• Biochemistry
• Proteomics
• Molecular Biology

Background:

• Proteolytic processing of proteins generates bioactive fragments crucial for cellular regulation, including angiogenesis.
• Identifying cleavage sites in extracellular matrix proteins is vital for understanding protein turnover and discovering new therapeutic targets.
• Traditional methods like Edman sequencing face limitations in throughput and resolution for complex protein fragments.

Purpose of the Study:

• To develop a novel, high-throughput method for identifying proteolytic cleavage sites in large proteins.
• To enable the discovery of new bioactive protein fragments involved in cellular processes and disease.
• To overcome the limitations of existing techniques for analyzing protein cleavage products.

Main Methods:

• Development of amino-terminal oriented mass spectrometry of substrates (ATOMS), a liquid chromatography-mass spectrometry approach.
• Utilizing dimethylation isotopic labeling for quantitative analysis of N-terminal fragments in solution.
• Employing a peptide-centric strategy independent of SDS-PAGE resolution limits.

Main Results:

• ATOMS reliably identifies multiple proteolytic sites in complex proteins per reaction.
• Fifty-five neutrophil elastase and 34 matrix metalloproteinase cleavage sites were identified in laminin-1 and fibronectin-1.
• The method demonstrates broad applicability for N-terminal identification in high molecular weight extracellular matrix proteins.

Conclusions:

• ATOMS provides a powerful alternative to Edman sequencing for identifying protein cleavage sites and fragments.
• This degradomics approach facilitates the discovery of novel bioactive peptides from extracellular matrix proteins.
• ATOMS has significant potential for applications in pathology and bioactivity screening of protease-generated fragments.