Accurate annotation of peptide modifications through unrestrictive database search

Area of Science:

• Biochemistry
• Proteomics
• Mass Spectrometry

Background:

• Post-translational modifications (PTMs) are crucial for protein function, cellular regulation, and signal transduction.
• Peptide tandem mass spectrometry is a key technology for discovering PTMs and sequence variations at the proteomic scale.
• Assessing the accuracy of PTM discovery is essential for reliable proteomic data.

Purpose of the Study:

• To develop and present methods for quantifying the false discovery rate in PTM discovery.
• To introduce PTMFinder, a tool designed to differentiate valid PTMs from search artifacts.
• To summarize identified PTMs from large-scale datasets.

Main Methods:

• Discussing methods for false discovery rate quantification in PTM searches.
• Utilizing distinct features to distinguish true modifications from artifacts.
• Implementing these methods within the PTMFinder software tool.

Main Results:

• Thousands of known and novel post-translational modification sites were identified.
• PTMFinder effectively distinguishes valid modifications from search artifacts.
• Site-specific modifications conserved across evolutionary distances were discovered.

Conclusions:

• Accurate assessment of PTM discovery is critical for proteomic studies.
• PTMFinder provides a valuable tool for improving the reliability of PTM identification.
• Large-scale proteomic analyses reveal extensive and evolutionarily conserved PTMs.