Quantitative Native Proteomics by Capillary Zone Electrophoresis-Mass Spectrometry

Area of Science:

• Proteomics
• Cellular Biology
• Analytical Chemistry

Background:

• Understanding protein complex dynamics is crucial for biological and medical research.
• Existing methods for measuring protein complex changes are limited.

Purpose of the Study:

• To establish and validate a capillary zone electrophoresis-mass spectrometry (CZE-MS)-based quantitative native proteomics approach.
• To investigate changes in protein complex abundance during the transition from logarithmic to stationary phase growth in Escherichia coli.

Main Methods:

• Developed a workflow integrating native CZE-MS for label-free quantification of complexoforms.
• Utilized in-source collision-induced dissociation for oligomeric state analysis.
• Employed denatured top-down proteomics for proteoform identification.

Main Results:

• Successfully quantified complexoform abundance changes during Escherichia coli growth.
• Identified differentially expressed complexoforms, including a higher abundance of the glutamate decarboxylase beta hexamer in stationary phase.
• Demonstrated the capability of the method to reveal biologically relevant protein complex dynamics.

Conclusions:

• This work presents the first quantitative native proteomics study utilizing online native CZE-MS.
• The established method provides a powerful tool for analyzing complexoform dynamics in biological systems.
• The findings highlight the utility of quantitative native proteomics in understanding cellular responses to growth phase transitions.