Identification of ligands for bacterial sensor proteins

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Bacterial signal transduction relies on sensor proteins, but their cognate signal molecules are often unknown.
• This knowledge gap hinders functional annotation and understanding of bacterial regulatory circuits, representing a significant bottleneck in the field.

Purpose of the Study:

• To address the bottleneck in identifying signal molecules for bacterial sensor proteins.
• To optimize high-throughput screening methods for ligand-binding domains (LBDs) to accelerate functional annotation.

Main Methods:

• Utilized high-throughput protein screening of commercially available ligand collections.
• Employed differential scanning fluorimetry (DSF) for ligand binding analysis.
• Investigated and addressed critical experimental design considerations for LBDs, including quaternary structure (dimeric state) and ligand-free apo-form generation.

Main Results:

• Identified key factors influencing ligand recognition by LBDs, specifically the requirement for the dimeric state in some cases.
• Demonstrated that pre-bound ligands in purified LBDs can inhibit further binding, necessitating apo-form generation.
• Showcased a protocol for generating the apo-form via denaturation and refolding to enable accurate ligand identification.

Conclusions:

• The refined screening approach, accounting for LBD dimerization and apo-form generation, significantly enhances the identification of signal molecules.
• This methodology will accelerate the functional annotation of bacterial sensor proteins, thereby advancing the understanding of bacterial regulatory networks.