Pré-Publication, Document De Travail Année : 2021

Protein-primed RNA synthesis in SARS-CoVs and structural basis for inhibition by AT-527

Camille Falcou
  • Fonction : Auteur
Pierre Gauffre
  • Fonction : Auteur
Priscila El Kazzi
  • Fonction : Auteur
Cécilia Eydoux
Jean-Claude Guillemot
  • Fonction : Auteur
Adel Moussa
  • Fonction : Auteur
Steven Good
  • Fonction : Auteur
Kai Lin
Jean-Pierre Sommadossi
  • Fonction : Auteur
Yingxiao Zhu
Xiaodong Yan
  • Fonction : Auteur
Hui Shi
  • Fonction : Auteur

Résumé

Summary How viruses from the Coronaviridae family initiate viral RNA synthesis is unknown. Here we show that the SARS-CoV-1 and −2 Ni dovirus R dRp- A ssociated N ucleotidyltransferase (NiRAN) domain on nsp12 uridylates the viral cofactor nsp8, forming a UMP-Nsp8 covalent intermediate that subsequently primes RNA synthesis from a poly(A) template; a protein-priming mechanism reminiscent of Picornaviridae enzymes. In parallel, the RdRp active site of nsp12 synthesizes a pppGpU primer, which primes (-)ssRNA synthesis at the precise genome-poly(A) junction. The guanosine analogue 5’-triphosphate AT-9010 (prodrug: AT-527) tightly binds to the NiRAN and inhibits both nsp8-labeling and the initiation of RNA synthesis. A 2.98 Å resolution Cryo-EM structure of the SARS-CoV-2 nsp12-nsp7-(nsp8) 2 /RNA/NTP quaternary complex shows AT-9010 simultaneously binds to both NiRAN and RdRp active site of nsp12, blocking their respective activities. AT-527 is currently in phase II clinical trials, and is a potent inhibitor of SARS-CoV-1 and −2, representing a promising drug for COVID-19 treatment.

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Dates et versions

hal-03367971 , version 1 (06-10-2021)

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Ashleigh Shannon, Véronique Fattorini, Bhawna Sama, Barbara Selisko, Mikael Feracci, et al.. Protein-primed RNA synthesis in SARS-CoVs and structural basis for inhibition by AT-527. 2021. ⟨hal-03367971⟩
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