Processing of the SARS-CoV pp1a/ab nsp7-10 region

Biochem J. 2020 Mar 13;477(5):1009-1019. doi: 10.1042/BCJ20200029.


Severe acute respiratory syndrome coronavirus is the causative agent of a respiratory disease with a high case fatality rate. During the formation of the coronaviral replication/transcription complex, essential steps include processing of the conserved polyprotein nsp7-10 region by the main protease Mpro and subsequent complex formation of the released nsp's. Here, we analyzed processing of the coronavirus nsp7-10 region using native mass spectrometry showing consumption of substrate, rise and fall of intermediate products and complexation. Importantly, there is a clear order of cleavage efficiencies, which is influenced by the polyprotein tertiary structure. Furthermore, the predominant product is an nsp7+8(2 : 2) hetero-tetramer with nsp8 scaffold. In conclusion, native MS, opposed to other methods, can expose the processing dynamics of viral polyproteins and the landscape of protein interactions in one set of experiments. Thereby, new insights into protein interactions, essential for generation of viral progeny, were provided, with relevance for development of antivirals.

Keywords: coronavirus; native mass spectrometry; polyprotein processing; structural virology.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Coronavirus 3C Proteases
  • Coronavirus Infections / genetics
  • Coronavirus RNA-Dependent RNA Polymerase
  • Cysteine Endopeptidases / chemistry
  • Cysteine Endopeptidases / genetics
  • Fluorescence Resonance Energy Transfer
  • Protein Structure, Secondary
  • RNA-Binding Proteins / chemistry
  • RNA-Binding Proteins / genetics*
  • Sequence Alignment / methods*
  • Viral Nonstructural Proteins / chemistry
  • Viral Nonstructural Proteins / genetics*
  • Viral Regulatory and Accessory Proteins / chemistry
  • Viral Regulatory and Accessory Proteins / genetics*
  • Virus Replication / physiology


  • NS8 protein, SARS-CoV-2
  • NSP10 protein, SARS-CoV-2
  • NSP9 protein, SARS-CoV-2
  • RNA-Binding Proteins
  • Viral Nonstructural Proteins
  • Viral Regulatory and Accessory Proteins
  • Coronavirus RNA-Dependent RNA Polymerase
  • NSP7 protein, SARS-CoV-2
  • Cysteine Endopeptidases
  • Coronavirus 3C Proteases