Fe-S cofactors in the SARS-CoV-2 RNA-dependent RNA polymerase are potential antiviral targets

Nunziata Maio,Tracey A Rouault,W Marston Linehan,Theodore C Pierson,Yan Li,J Martin Bollinger,Debangsu Sil,Bernard A P Lafont,Carsten Krebs

doi:10.1126/science.abi5224

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causal agent of coronavirus disease 2019 (COVID-19), uses an RNA-dependent RNA polymerase (RdRp) for the replication of its genome and the transcription of its genes. We found that the catalytic subunit of the RdRp, nsp12, ligates two iron-sulfur metal cofactors in sites that were modeled as zinc centers in the available cryo-electron microscopy structures of the RdRp complex. These metal binding sites are essential for replication and for interaction with the viral helicase. Oxidation of the clusters by the stable nitroxide TEMPOL caused their disassembly, potently inhibited the RdRp, and blocked SARS-CoV-2 replication in cell culture. These iron-sulfur clusters thus serve as cofactors for the SARS-CoV-2 RdRp and are targets for therapy of COVID-19.

Highlights

The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) has caused a global pandemic known as COVID-19 (1–3), which can be prevented by vaccines but for which antiviral treatments are much needed
To assess whether the LYR-like motifs were involved in direct binding of nsp[12] to HSC20, we incubated full-length SARS-CoV-2 nsp[12] wild type (WT) or variants wherein either or both LYR motifs were replaced by alanines (A)
Substitution of either of the two LYR motifs with alanines decreased the amount of bound HSC20 (Fig. 1A), which was even more profoundly diminished by loss of both motifs in nsp12VYR/LYR-AAA (Fig. 1A)

Summary

Introduction

The novel coronavirus severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) has caused a global pandemic known as COVID-19 (1–3), which can be prevented by vaccines but for which antiviral treatments are much needed. The nsp12nsp7-nsp[8] complex anoxically purified with the Fe-S cluster(s) showed markedly increased binding to the template and RNA primer

Results

Conclusion