SARS-CoV-2 is the pathogen responsible for the COVID-19 pandemic. The SARS-CoV-2 papain-like cysteine protease (PLpro) has been implicated in playing important roles in virus maturation, dysregulation of host inflammation, and antiviral immune responses. The multiple functions of PLpro render it a promising drug target. Therefore, we screened a library of approved drugs and also examined available inhibitors against PLpro. Inhibitor GRL0617 showed a promising in vitro IC 50 of 2.1 μM and an effective antiviral inhibition in cell-based assays. The co-crystal structure of SARS-CoV-2 PLpro C111S in complex with GRL0617 indicates that GRL0617 is a non-covalent inhibitor and it resides in the ubiquitin-specific proteases (USP) domain of PLpro. NMR data indicate that GRL0617 blocks the binding of ISG15 C-terminus to PLpro. Using truncated ISG15 mutants, we show that the C-terminus of ISG15 plays a dominant role in binding PLpro. Structural analysis reveals that the ISG15 C-terminus binding pocket in PLpro contributes a disproportionately large portion of binding energy, thus this pocket is a hot spot for antiviral drug discovery targeting PLpro. The SARS-CoV-2 papain-like protease (PLpro) is of interest as a drug target. Here, the authors identify GRL0617 as a PPI (protein–protein interaction) inhibitor of SARS-CoV-2 PLpro that inhibits its deISGylating activity and present the mechanism of action of the compound through the GRL0617-bound PLpro crystal structure and NMR studies.
【저자키워드】 viral infection, Drug discovery, structural biology, Nanocrystallography, 【초록키워드】 SARS-CoV-2, Inflammation, Antiviral, COVID-19 pandemic, in vitro, virus, inhibitors, antiviral drug, binding energy, approved drugs, Papain-like protease, pathogen, immune responses, hot spot, drug target, mutants, crystal structure, PLPro, inhibitor, mechanism of action, mechanism, function, NMR, binding, Protein–protein interaction, ISG15, Analysis, PPI, Structural analysis, dysregulation, cysteine, approved drug, maturation, complex, Compound, domain, cysteine protease, binding pocket, library, C-terminus, antiviral immune responses, block, dominant, Host, effective, responsible, identify, examined, assays, inhibit, screened, indicate, contribute, reveal, implicated, 【제목키워드】 SARS-CoV-2, antiviral drug, hot spot, complex, reveal,