Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the current coronavirus disease 2019 (COVID-19) pandemic. A major virulence factor of SARS-CoVs is the nonstructural protein 1 (Nsp1), which suppresses host gene expression by ribosome association. Here, we show that Nsp1 from SARS-CoV-2 binds to the 40 S ribosomal subunit, resulting in shutdown of messenger RNA (mRNA) translation both in vitro and in cells. Structural analysis by cryo-electron microscopy of in vitro-reconstituted Nsp1-40 S and various native Nsp1-40 S and -80 S complexes revealed that the Nsp1 C terminus binds to and obstructs the mRNA entry tunnel. Thereby, Nsp1 effectively blocks retinoic acid-inducible gene I-dependent innate immune responses that would otherwise facilitate clearance of the infection. Thus, the structural characterization of the inhibitory mechanism of Nsp1 may aid structure-based drug design against SARS-CoV-2.
Organizational Affiliation:
Gene Center Munich, Department of Biochemistry, University of Munich, Munich, Germany.
Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany.
Laboratory of Functional Genome Analysis, University of Munich, Munich, Germany.
Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany. beckmann@genzentrum.lmu.de konstantin.sparrer@uni-ulm.de.
Gene Center Munich, Department of Biochemistry, University of Munich, Munich, Germany. beckmann@genzentrum.lmu.de konstantin.sparrer@uni-ulm.de.
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