Substrate-Based Ligand Design for Phenazine Biosynthesis Enzyme PhzF.

Area of Science:

• Microbiology
• Biochemistry
• Drug Discovery

Background:

• Pseudomonas aeruginosa is a WHO priority pathogen due to antibiotic resistance.
• Pyocyanin is a key virulence factor produced by P. aeruginosa.
• Targeting virulence factors offers a strategy to combat antibiotic resistance by reducing pathogenicity without killing bacteria.

Purpose of the Study:

• To investigate the isomerase PhzF as a potential pathoblocker target.
• To design and synthesize inhibitors of PhzF based on 3-hydroxyanthranilic acid derivatives.
• To understand the structural basis for PhzF inhibition.

Main Methods:

• Structure-based drug design using crystal structures of PhzF.
• Synthesis of 3-hydroxyanthranilic acid derivatives.
• Co-crystallization of PhzF with synthesized inhibitors.
• Fluorescence resonance energy transfer (FRET) assays for affinity determination.
• Structure-activity relationship (SAR) analysis.

Main Results:

• Co-crystal structures revealed binding pocket limitations in the closed conformation of PhzF.
• Ligand binding was more amenable to modification in the open conformation of PhzF.
• The carboxylic acid group of the inhibitors was found to be essential for binding to PhzF.
• Intrinsic fluorescence of derivatives facilitated direct affinity measurements.

Conclusions:

• The study provides crucial structural insights into PhzF inhibition.
• These findings will guide the rational design of novel PhzF inhibitors.
• This research contributes to developing pathoblocker strategies against P. aeruginosa.