An agarose-acrylamide composite native gel system suitable for separating ultra-large protein complexes.

Area of Science:

• Biochemistry
• Molecular Biology
• Proteomics

Background:

• Analyzing large protein complexes and their interactions is crucial for understanding cellular functions.
• Existing methods often struggle with resolving ultra-large protein complexes (over 500kDa) in their native states.

Purpose of the Study:

• To develop and validate a novel agarose-acrylamide composite native gel (CNG) system.
• To enable the separation and analysis of ultra-large protein complexes and their native interactions.
• To provide a robust platform for studying dynamic protein-protein interactions.

Main Methods:

• Exploration of various native gel conditions and technique optimization for CNG system formation and performance.
• Demonstration of CNG electrophoresis for resolving specific protein complexes.
• Coupling of CNG electrophoresis with second-dimension SDS-PAGE for protein component identification.

Main Results:

• The CNG system successfully separated ultra-large protein complexes (>500kDa) in their native states.
• A complex of RNA polymerase II and an associated factor was resolved, a feat not previously achieved.
• The technique was validated for capturing dynamic protein-protein interactions, exemplified by the RNA polymerase II-Fcp1 complex.

Conclusions:

• The developed CNG system is a powerful tool for separating and analyzing large native protein complexes.
• This technique overcomes limitations of previous methods for studying protein-protein interactions.
• CNG electrophoresis coupled with SDS-PAGE offers a comprehensive approach for proteomic analysis.