Structure-Based Development of a Covalent Inhibitor Targeting Streptococcus Pyogenes over Staphylococcus Aureus...

Area of Science:

• Microbiology
• Drug Discovery
• Structural Biology

Background:

• Sortase A (SrtA) is a critical enzyme in Gram-positive pathogens for surface protein anchoring.
• Existing covalent SrtA inhibitors lack species selectivity, limiting their therapeutic application.
• Developing narrow-spectrum antivirulence agents is crucial for targeted treatment strategies.

Purpose of the Study:

• To design and develop a novel covalent inhibitor targeting Streptococcus pyogenes Sortase A (SpSrtA) with high species selectivity.
• To investigate the structural basis for selective inhibition of SpSrtA over Staphylococcus aureus SrtA (SaSrtA).
• To evaluate the in vitro and in vivo efficacy of the developed inhibitor as an antivirulence agent.

Main Methods:

• Structure-guided drug design and molecular docking were employed to optimize lead compounds.
• X-ray crystallography was used to confirm the covalent interaction of the inhibitor with the target enzyme.
• In vitro assays assessed inhibitory potency, species selectivity, and effects on M-protein anchoring and biofilm formation.
• In vivo efficacy was evaluated using a Galleria mellonella infection model.

Main Results:

• A novel covalent inhibitor, T10, was developed, demonstrating selective inhibition of SpSrtA.
• Molecular docking and X-ray crystallography elucidated the structural basis for T10's selectivity, involving steric hindrance in SaSrtA.
• T10 exhibited enhanced inhibitory potency against SpSrtA and specifically disrupted M-protein anchoring and biofilm formation in Streptococcus pyogenes.
• T10 showed no adverse effects on Staphylococcus aureus viability and provided significant protection in a Galleria mellonella infection model.

Conclusions:

• Structure-based rational design can yield narrow-spectrum antivirulence agents.
• T10 represents a promising lead compound for developing targeted therapies against Streptococcus pyogenes infections.
• Selective inhibition of SrtA offers a viable antivirulence strategy with reduced risk of off-target effects.