Picomole-scale characterization of protein stability and function by quantitative cysteine reactivity

Area of Science:

• Biochemistry
• Biophysics
• Molecular Biology

Background:

• Protein stability, the Gibbs free energy difference between native and unfolded states, is a fundamental characteristic.
• Protein stability is thermodynamically linked to ligand binding, offering a universal monitor of biochemical function.
• Traditional stability measurements require large protein amounts and specialized equipment, limiting their widespread use.

Purpose of the Study:

• To introduce a novel technique for rapid and accurate determination of protein stabilities.
• To enable the use of stability measurements as a functional probe with minimal sample and equipment requirements.

Main Methods:

• Development and application of the quantitative cysteine reactivity (QCR) technique.
• Utilizing picomole quantities of protein and standard laboratory equipment.

Main Results:

• QCR accurately determines protein stabilities.
• QCR-derived stabilities effectively measure protein-ligand binding across a broad range of concentrations and affinities.

Conclusions:

• The QCR technique provides a sensitive and efficient method for assessing protein stability and ligand interactions.
• This method has broad applications in high-throughput protein engineering and functional genomics.