An E. coli display method for characterization of peptide-sensor kinase interactions

Area of Science:

• Microbiology
• Molecular Biology
• Biochemistry

Background:

• Bacteria utilize two-component system (TCS) signaling pathways to perceive and react to peptides.
• These peptides are crucial for host defense, quorum sensing, and inter-bacterial interactions.
• The full range of peptide-sensing capabilities of TCSs remains largely unexplored.

Purpose of the Study:

• To investigate the peptide-sensing capabilities of the Salmonella Typhimurium two-component system PhoPQ.
• To characterize the impact of human antimicrobial peptides (AMPs) on PhoPQ activity.
• To identify specific peptide features and sub-domains that activate PhoPQ.

Main Methods:

• Development of an Escherichia coli display method for high-throughput screening.
• Characterization of diverse human antimicrobial peptides (AMPs) and their variants.
• Application of machine learning algorithms to analyze peptide-TCS interactions.

Main Results:

• The Salmonella Typhimurium PhoPQ system senses AMPs with varied sequences, structures, and functions.
• Identification of specific peptide sub-domains and biophysical characteristics that trigger PhoPQ activation.
• Discovery that many novel AMP activators induce PhoPQ in S. Typhimurium, potentially influencing virulence.

Conclusions:

• The study reveals broad peptide-sensing capabilities of the PhoPQ TCS.
• New insights into the evolution of peptide-sensing specificity across bacterial species were gained.
• The developed method facilitates deeper understanding of TCS-mediated peptide sensing mechanisms and evolution.