Remdesivir is a direct-acting antiviral that inhibits RNA-dependent RNA polymerase from severe acute respiratory syndrome coronavirus 2 with high potency

• Published in: The Journal of biological chemistry Vol. 295; no. 20; pp. 6785 - 6797
• Main Authors: Gordon, Calvin J., Tchesnokov, Egor P., Woolner, Emma, Perry, Jason K., Feng, Joy Y., Porter, Danielle P., Götte, Matthias
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 15.05.2020; American Society for Biochemistry and Molecular Biology
• Subjects: Adenosine Monophosphate - analogs & derivatives; Adenosine Monophosphate - pharmacology; Alanine - analogs & derivatives; Alanine - pharmacology; Animals; Antiviral Agents - pharmacology; Betacoronavirus - enzymology; Betacoronavirus - physiology; coronavirus (CoV); COVID-19; drug action; drug development; drug discovery; Ebola virus; Editors' Picks; favipiravir; Lassa virus; MERS; Models, Molecular; plus-stranded RNA virus; remdesivir; replication; ribavirin; RNA polymerase; RNA-dependent RNA polymerase (RdRp); RNA-Dependent RNA Polymerase - antagonists & inhibitors; SARS; SARS-CoV-2; Sf9 Cells; sofosbuvir; Spodoptera; Virus Replication - drug effects; replication; ribavirin; drug development; SARS; RNA polymerase; Lassa virus; remdesivir; COVID-19; Ebola virus; sofosbuvir; RNA-dependent RNA polymerase (RdRp); SARS-CoV-2; drug discovery; drug action; plus-stranded RNA virus; coronavirus (CoV); MERS; favipiravir
• ISSN: 0021-9258; 1083-351X; 1083-351X
• DOI: 10.1074/jbc.RA120.013679

Effective treatments for coronavirus disease 2019 (COVID-19) are urgently needed to control this current pandemic, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Replication of SARS-CoV-2 depends on the viral RNA-dependent RNA polymerase (RdRp), which is the likely target of the investigational nucleotide analogue remdesivir (RDV). RDV shows broad-spectrum antiviral activity against RNA viruses, and previous studies with RdRps from Ebola virus and Middle East respiratory syndrome coronavirus (MERS-CoV) have revealed that delayed chain termination is RDV's plausible mechanism of action. Here, we expressed and purified active SARS-CoV-2 RdRp composed of the nonstructural proteins nsp8 and nsp12. Enzyme kinetics indicated that this RdRp efficiently incorporates the active triphosphate form of RDV (RDV-TP) into RNA. Incorporation of RDV-TP at position i caused termination of RNA synthesis at position i+3. We obtained almost identical results with SARS-CoV, MERS-CoV, and SARS-CoV-2 RdRps. A unique property of RDV-TP is its high selectivity over incorporation of its natural nucleotide counterpart ATP. In this regard, the triphosphate forms of 2′-C-methylated compounds, including sofosbuvir, approved for the management of hepatitis C virus infection, and the broad-acting antivirals favipiravir and ribavirin, exhibited significant deficits. Furthermore, we provide evidence for the target specificity of RDV, as RDV-TP was less efficiently incorporated by the distantly related Lassa virus RdRp, and termination of RNA synthesis was not observed. These results collectively provide a unifying, refined mechanism of RDV-mediated RNA synthesis inhibition in coronaviruses and define this nucleotide analogue as a direct-acting antiviral.