A quantitative, high-throughput screen for protein stability

Area of Science:

• Proteomics
• Biophysical Chemistry
• Mass Spectrometry

Background:

• Assessing protein structural stability is vital in proteomic research.
• Current methods for protein stability assessment are often time-consuming and require purified samples.
• A high-throughput method for analyzing unpurified protein stability is needed.

Purpose of the Study:

• To introduce and validate a novel technique, Stability of Unpurified Proteins from rates of H/D exchange (SUPREX), for measuring protein stability.
• To demonstrate the applicability of SUPREX for rapid, high-throughput screening of protein stability in unpurified samples.
• To compare SUPREX results with conventional methods and assess its precision across various stability ranges.

Main Methods:

• Utilizing hydrogen deuterium exchange (H/D exchange) coupled with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS).
• Measuring microgram quantities of unpurified protein extracts.
• Employing SUPREX to determine the stability of proteins like maltose binding protein and lambda repressor variants.

Main Results:

• SUPREX results for maltose binding protein and lambda repressor variants showed strong agreement with conventional circular dichroism (CD) denaturation data.
• The method successfully detected changes in protein stability upon ligand binding, such as maltose binding to maltose binding protein.
• SUPREX demonstrated high precision across a broad spectrum of protein stabilities.

Conclusions:

• SUPREX provides a rapid, high-throughput, and accurate method for assessing protein stability using unpurified samples.
• This technique is valuable for proteomic research, enabling efficient screening of protein structural integrity.
• SUPREX offers a precise and versatile tool for biophysical characterization of proteins and their interactions.