Scalable Inhibitors of the Nsp3-Nsp4 Coupling in SARS-CoV-2

Area of Science:

• Virology and Drug Discovery
• Structural Biology and Molecular Modeling

Background:

• SARS-CoV-2 pandemic necessitates novel therapeutic strategies beyond existing antivirals.
• Viral nonstructural proteins (Nsps), particularly Nsp4, are crucial for viral replication and represent promising drug targets.
• Nsp4's role in double-membrane vesicle formation and its conservation across Betacoronaviruses make it an attractive target.

Purpose of the Study:

• To identify and characterize novel inhibitors of SARS-CoV-2 Nsp4.
• To explore alternative therapeutic approaches targeting the viral membrane rearrangement system.
• To investigate the potential of Nsp3-based peptide inhibitors and dendrimer-conjugated therapeutics.

Main Methods:

• Utilized AlphaFold2 to generate high-resolution structures of Nsp3 and Nsp4 lumenal loops.
• Performed virtual screening of 7 million ligands using molecular docking against Nsp4.
• Conducted molecular dynamics (MD) simulations to assess ligand-protein complex stability and binding interactions.
• Designed and simulated Nsp3-based peptide inhibitors and dendrimer-conjugated therapeutics.

Main Results:

• Identified five lead-like compounds as putative Nsp4 inhibitors with favorable properties and stable MD simulations.
• Nsp3-based peptide inhibitors demonstrated stable binding to Nsp4 in MD simulations.
• Dendrimer conjugation enhanced multivalent binding to Nsp4, particularly its large flexible luminal loop (Nsp4LLL).

Conclusions:

• This study presents a novel therapeutic strategy targeting the viral membrane rearrangement machinery.
• Identified small-molecule and peptide inhibitors, along with dendrimer conjugates, show potential for treating SARS-CoV-2 and similar viruses.
• The findings open a new avenue for antiviral drug development focused on essential viral replication components.