Stalling the Enemy: Targeting Nsp13 for Next-Generation SARS-CoV-2 Antivirals

Area of Science:

• Virology
• Drug Discovery
• Biochemistry

Background:

• The emergence of drug-resistant SARS-CoV-2 strains necessitates novel antiviral therapeutics targeting essential viral proteins.
• The SARS-CoV-2 nonstructural protein 13 (nsp13) RNA helicase is crucial for viral replication and a promising drug target.

Purpose of the Study:

• To identify inhibitors of the SARS-CoV-2 nsp13 RNA helicase.
• To characterize potential antiviral compounds targeting nsp13.

Main Methods:

• Ultra-high-throughput nucleic acid unwinding assay screening of FDA-approved drugs and bioactive compounds.
• Biochemical, biophysical characterization, and Hydrogen-deuterium exchange Mass Spectrometry (HDX-MS) studies.
• Antiviral activity testing against infectious SARS-CoV-2 in cell lines.

Main Results:

• Forty nsp13 inhibitors were identified with IC50 values between 1.4 and 10 μM.
• Four compounds demonstrated nsp13 binding without affecting nucleic acid substrate or ATPase activity.
• HDX-MS revealed compound-induced conformational changes in nsp13.
• Identified compounds exhibited antiviral activity against SARS-CoV-2, though cytotoxicity was observed in some cases.

Conclusions:

• Novel nsp13 inhibitors were discovered, offering a new avenue for antiviral drug development.
• These compounds show potential for therapeutic strategies against current and future coronavirus threats.
• Further optimization is needed to enhance efficacy and mitigate cytotoxicity for clinical application.