Journal Article

Mechanism of molnupiravir-induced SARS-CoV-2 mutagenesis

Kokic, Goran, Dienemann, Christian, Cramer, Patrick, Kabinger, Florian, Höbartner, Claudia, Schmitzová, Jana, Hillen, Hauke S., Stiller, Carina

2021

Overview

Molnupiravir is an orally available antiviral drug candidate currently in phase III trials for the treatment of patients with COVID-19. Molnupiravir increases the frequency of viral RNA mutations and impairs SARS-CoV-2 replication in animal models and in humans. Here, we establish the molecular mechanisms underlying molnupiravir-induced RNA mutagenesis by the viral RNA-dependent RNA polymerase (RdRp). Biochemical assays show that the RdRp uses the active form of molnupiravir, β- d - N 4 -hydroxycytidine (NHC) triphosphate, as a substrate instead of cytidine triphosphate or uridine triphosphate. When the RdRp uses the resulting RNA as a template, NHC directs incorporation of either G or A, leading to mutated RNA products. Structural analysis of RdRp–RNA complexes that contain mutagenesis products shows that NHC can form stable base pairs with either G or A in the RdRp active center, explaining how the polymerase escapes proofreading and synthesizes mutated RNA. This two-step mutagenesis mechanism probably applies to various viral polymerases and can explain the broad-spectrum antiviral activity of molnupiravir. Quantitative biochemical assays and high-resolution cryo-EM analysis reveal how the COVID-19 antiviral drug candidate molnupiravir causes lethal viral mutagenesis by the RNA-dependent RNA polymerase (RdRp) of SARS-CoV-2.

• Publisher: Nature Publishing Group US,Nature Publishing Group
• Subject: 101/28 / 631/45/535/1258/1259 / 631/535/1258/1259 / 82 / Animal models / Animals / Antiviral activity / Antiviral agents / Antiviral Agents - chemistry / Antiviral Agents - metabolism / Antiviral Agents - pharmacology / Antiviral drugs / Base Sequence / Biochemistry / Biological Microscopy / Biomedical and Life Sciences / Chemical properties / Clinical trials / Coronaviruses / COVID-19 / COVID-19 - prevention & control / COVID-19 - virology / COVID-19 Drug Treatment / CTP / Cytidine - analogs & derivatives / Cytidine - chemistry / Cytidine - metabolism / Cytidine - pharmacology / Cytidine triphosphate / DNA-directed RNA polymerase / Editing / Evaluation / Humans / Hydroxylamines - chemistry / Hydroxylamines - metabolism / Hydroxylamines - pharmacology / Life Sciences / Membrane Biology / Models, Molecular / Molecular modelling / Molecular Structure / Mutagenesis / Mutagenesis - drug effects / Mutagenesis - genetics / Mutation / Mutation - drug effects / Mutation - genetics / Nucleic Acid Conformation / Proofreading / Protein Binding - drug effects / Protein Conformation / Protein Structure / RNA polymerase / RNA, Viral - chemistry / RNA, Viral - genetics / RNA, Viral - metabolism / RNA-Dependent RNA Polymerase - chemistry / RNA-Dependent RNA Polymerase - genetics / RNA-Dependent RNA Polymerase - metabolism / RNA-directed RNA polymerase / SARS-CoV-2 - drug effects / SARS-CoV-2 - genetics / SARS-CoV-2 - physiology / Severe acute respiratory syndrome coronavirus 2 / Structural analysis / Substrates / Uridine / Virus Replication - drug effects / Virus Replication - genetics