Optimized Microscale Protein Aggregation Suppression Assay: A Method for Evaluating the Holdase Activity of...

Area of Science:

• Biochemistry
• Molecular Biology

Background:

• Molecular chaperones prevent protein aggregation by binding exposed hydrophobic regions.
• Holdase activity, a key chaperone function, is typically measured by suppressing heat-induced protein aggregation.
• Standard assays require substantial protein, limiting their use for low-abundance chaperones.

Purpose of the Study:

• To develop a miniaturized, cost-effective assay for measuring molecular chaperone holdase activity.
• To adapt existing aggregation suppression assays for use with limited protein quantities.
• To enable broader application of holdase activity measurements for characterization and inhibitor screening.

Main Methods:

• Developed miniaturized absorbance and fluorescence-based assays.
• Utilized DnaK from Escherichia coli as a model chaperone.
• Employed heat-induced aggregation of malate dehydrogenase as a model substrate.
• Compared performance against standard aggregation suppression assays.

Main Results:

• The miniaturized assays effectively measure holdase activity using significantly less protein.
• The protocol is affordable and adaptable for various low-abundance holdases.
• Demonstrated successful application using DnaK and malate dehydrogenase.

Conclusions:

• Miniaturized holdase activity assays provide a valuable tool for biochemical and molecular biology research.
• The developed protocol facilitates fundamental characterization of holdase function.
• Enables efficient screening for inhibitors of chaperone holdase activity, particularly for low-abundance proteins.