Ultrahigh Resolution and Quantitative Analysis of Native Protein Assembly Intermediates by Multistack...

Area of Science:

• Biochemistry
• Structural Biology
• Analytical Chemistry

Background:

• Distinguishing native protein assemblies from intermediates is difficult due to limited resolution of standard methods.
• Subtle differences in size and shape of protein oligomers pose analytical challenges.

Purpose of the Study:

• To introduce Conformation-Specific Electrophoresis (CSE), a novel technique for high-resolution separation of native protein oligomers.
• To demonstrate CSE's capability in resolving complex protein assembly intermediates.

Main Methods:

• Developed a multistack gel electrophoresis strategy (CSE) with tailored polyacrylamide stacks.
• Employed iterative focusing and differential sieving for separation based on shape and mass.
• Utilized a pore-forming toxin as a model system for validation.

Main Results:

• CSE achieved subunit-resolution separation of all unique protein assembly intermediates.
• The method resolved complex mixtures where conventional electrophoresis showed only overlapping bands.
• Demonstrated high resolution, analytical linearity, and sensitivity for quantifying trace oligomers.
• Confirmed the nondenaturing nature of CSE through gel excision and subsequent analysis.

Conclusions:

• CSE provides a practical, high-resolution platform for studying protein assembly mechanisms.
• The technique is broadly applicable for characterizing molecular heterogeneity in various scientific fields.
• CSE enables isolation of functional oligomers for further advanced analyses.