Structure-Guided Design of Proteomimetics Targeting the SARS-CoV-2 S-RBD/hACE2 Interface.

Area of Science:

• Biochemistry
• Structural Biology
• Drug Discovery

Background:

• The SARS-CoV-2 Spike receptor-binding domain (S-RBD)/hACE2 interaction is a difficult target for drug development due to its large, shallow binding interface.
• Protein-protein interactions (PPIs) are crucial in viral entry mechanisms, making them key targets for antiviral therapies.

Purpose of the Study:

• To design and validate novel constrained peptidomimetics that inhibit the SARS-CoV-2 S-RBD/hACE2 interaction.
• To establish a proof-of-concept for proteomimetics as effective inhibitors of challenging PPIs.

Main Methods:

• In silico alanine mutagenesis was used to guide structure-based design of peptidomimetics.
• Peptide stapling and head-to-tail macrocyclization strategies were employed to stabilize secondary structure mimetics.
• Covalent linkage of α1-helix and β-sheet mimetics created proteomimetic 28.

Main Results:

• Proteomimetic 28 selectively binds SARS-CoV-2 S-RBD and disrupts the S-RBD/hACE2 interaction.
• Compound 28 inhibited pseudovirus entry with an IC50 of 6.6 μM.
• 28 demonstrated high stability (>24 h half-life) and low permeability in lung epithelial models.

Conclusions:

• Constrained proteomimetics can effectively inhibit challenging protein-protein interactions like the SARS-CoV-2 S-RBD/hACE2 interaction.
• Proteomimetic 28 shows promise as an antiviral agent with potential for intranasal delivery.
• This study validates proteomimetics as a viable strategy for targeting difficult PPIs.