Aptamer microarray as a novel bioassay for protein-protein interaction discovery and analysis

Area of Science:

• Biochemistry
• Molecular Biology
• Bioanalytical Chemistry

Background:

• Protein-protein interactions (PPIs) are crucial for cellular functions.
• Discovering and analyzing PPIs is essential for understanding biological processes.
• Novel bioassays are needed for efficient PPI discovery.

Purpose of the Study:

• To investigate aptamer microarrays as a novel bioassay for PPI discovery and analysis.
• To identify unknown protein interactions involving thrombin and Escherichia coli proteins.
• To explore the potential of aptamer microarrays for analyzing complex interaction networks.

Main Methods:

• Aptamer microarray assay using fluorescence-labeled thrombin and E. coli proteins.
• Confirmation of PPIs using protein microarrays and aptamer-baited co-immunoprecipitation (Co-IP).
• Identification of interacting proteins via SDS-PAGE and characterization of interaction kinetics using dose-response and competition assays.

Main Results:

• Aptamer microarray detected a PPI between thrombin and an unknown E. coli protein (protein X).
• Protein X was identified as E. coli Dps protein, a substrate for thrombin.
• The apparent dissociation constant for the PPI was determined to be 1.33 μM.
• On-microarray competition assays revealed the potential for analyzing protein-DNA and DNA-DNA interactions.

Conclusions:

• Aptamer microarrays are effective for discovering and analyzing protein-protein interactions.
• The study identified a novel interaction between thrombin and E. coli Dps protein.
• Aptamer microarrays offer a versatile platform for investigating complex biological interaction networks beyond simple PPIs.