ABSTRACT
The development of novel antivirals is crucial not only for managing current COVID-19 infections but for addressing potential future zoonotic outbreaks. SARS-CoV-2 main protease (Mpro) is vital for viral replication and viability and therefore serves as an attractive target for antiviral intervention. Herein, we report the optimization of a cyclic peptide inhibitor that emerged from an mRNA display selection against the SARS-CoV-2 Mpro to enhance its cell permeability and inâ vitro antiviral activity. By identifying mutation-tolerant amino acid residues within the peptide sequence, we describe the development of a second-generation Mpro inhibitor bearing five cyclohexylalanine residues. This cyclic peptide analogue exhibited significantly improved cell permeability and antiviral activity compared to the parent peptide. This approach highlights the importance of optimizing cyclic peptide hits for activity against intracellular targets such as the SARS-CoV-2 Mpro.
Subject(s)
Antiviral Agents , Coronavirus 3C Proteases , Hydrophobic and Hydrophilic Interactions , Peptides, Cyclic , SARS-CoV-2 , Peptides, Cyclic/chemistry , Peptides, Cyclic/pharmacology , Antiviral Agents/chemistry , Antiviral Agents/pharmacology , SARS-CoV-2/drug effects , SARS-CoV-2/enzymology , Coronavirus 3C Proteases/antagonists & inhibitors , Coronavirus 3C Proteases/metabolism , Coronavirus 3C Proteases/chemistry , Humans , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Amino Acids/chemistry , COVID-19 Drug TreatmentABSTRACT
Cytochrome-P450-mediated cross-linking of ribosomally encoded peptides (RiPPs) is rapidly expanding and displays great potential for biocatalysis. Here, we demonstrate that active site engineering of the biarylitide cross-linking enzyme P450Blt enables the formation of His-X-Tyr and Tyr-X-Tyr cross-linked peptides, thus showing how such P450s can be further exploited to produce alternate cyclic tripeptides with controlled cross-linking states.