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Updated: May 21, 2026
08:25
Phage-mediated Delivery of Targeted sRNA Constructs to Knock Down Gene Expression in E. coli
Published on: March 20, 2016
Structural engineering of a phage lysin that targets gram-negative pathogens
Petra Lukacik1, Travis J Barnard, Paul W Keller
1Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
Summary
Scientists developed a novel hybrid toxin to combat antibiotic-resistant gram-negative bacteria. This engineered phage therapy reagent targets specific bacterial transporters, offering a promising alternative to traditional antibiotics.
Area of Science:
- Structural biology
- Microbiology
- Drug discovery
Background:
- Antibiotic resistance in bacterial pathogens necessitates alternative therapies.
- Phage therapy using viral lysins is effective against gram-positive bacteria but not gram-negative due to the outer membrane barrier.
- Gram-negative bacteria possess outer membrane transporters that can be targeted.
Purpose of the Study:
- To investigate the structure of Yersinia pestis outer membrane transporter FyuA and its cognate toxin, pesticin.
- To design a novel antimicrobial agent effective against gram-negative bacteria.
- To develop a phage therapy reagent that overcomes limitations of existing treatments.
Main Methods:
- Determined the crystal structures of FyuA, a TonB-dependent transporter, and pesticin.
- Designed a hybrid toxin by fusing the FyuA binding domain of pesticin to phage T4 lysozyme.
- Assessed the efficacy and specificity of the hybrid toxin against Yersinia and E. coli strains.
Main Results:
- The crystal structure revealed pesticin's two-domain structure, with one domain binding FyuA.
- The engineered hybrid toxin effectively kills specific Yersinia and pathogenic E. coli strains.
- The hybrid toxin evades pesticin immunity protein (Pim) and targets virulence-associated FyuA on pathogenic bacteria.
Conclusions:
- The hybrid toxin represents a novel strategy for targeting gram-negative bacterial infections.
- This approach overcomes the outer membrane barrier and pesticin immunity.
- Targeting FyuA offers specificity towards pathogenic bacteria, preserving beneficial gut flora.
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