Preparation, FPLC Purification and LC-FT-ICR-MS of Proteins

Area of Science:

• Biochemistry
• Analytical Chemistry
• Proteomics

Background:

• High magnetic field Fourier transform ion cyclotron resonance (FT-ICR) mass spectrometry offers exceptional mass resolution, surpassing other techniques for protein analysis.
• This capability allows for the detailed examination of isotopic peak clusters, revealing information often missed by conventional mass spectrometers.

Purpose of the Study:

• To detail a protocol for the purification and subsequent identification of DNA-binding proteins and their modifications.
• To leverage the high resolution of FT-ICR mass spectrometry for precise protein quantitation and characterization.

Main Methods:

• Cellular extracts were prepared and DNA-binding proteins were purified using multiple chromatographic techniques with fast protein liquid chromatography (FPLC).
• Purified proteins were analyzed using liquid chromatography coupled to Fourier transform ion cyclotron resonance mass spectrometry (LC-FT-ICR-MS) for identification and quantitation.

Main Results:

• The protocol enables the identification and quantitation of protein isoforms and their post-translational modifications (PTMs).
• High-resolution FT-ICR mass spectrometry successfully distinguished between closely related PTMs, such as acetylation and trimethylation.

Conclusions:

• This protocol provides a robust method for in-depth proteomic analysis, particularly for DNA-binding proteins.
• The application of LC-FT-ICR-MS allows for the precise characterization of protein heterogeneity and PTMs, advancing the field of proteomics.