Expedited SARS-CoV-2 Main Protease Inhibitor Discovery through Modular 'Direct-to-Biology' Screening.

Area of Science:

• Medicinal Chemistry
• Drug Discovery
• Biochemistry

Background:

• Reactive fragment (RF) screening is effective for ligand discovery but optimization is often low-throughput.
• Traditional optimization requires extensive synthesis and purification, limiting efficiency.

Purpose of the Study:

• To develop and validate an efficient direct-to-biology (D2B) screening platform for reactive fragment optimization.
• To accelerate the discovery and optimization of inhibitors for SARS-CoV-2 main protease (MPro).

Main Methods:

• Developed a D2B screening platform for cysteine-targeting chloroacetamide RFs using 384-well plate synthesis.
• Performed direct biological assessment without compound purification.
• Applied the platform to optimize inhibitors of SARS-CoV-2 MPro.

Main Results:

• Successfully optimized an initial RF hit into potent MPro inhibitors.
• Demonstrated a 'switch' from covalent to reversible inhibitor series using D2B screening.
• Achieved accelerated optimization of RFs towards covalent and non-covalent inhibitor candidates.

Conclusions:

• The D2B platform significantly enhances the efficiency of RF optimization for drug discovery.
• This approach accelerates the development of covalent inhibitor candidates and facilitates exploration of non-covalent ligands.
• The D2B strategy offers a promising future direction for optimizing reactive fragments into diverse ligand types.