D614G Mutation Alters SARS-CoV-2 Spike Conformation and Enhances Protease Cleavage at the S1/S2 Junction

Cell Rep. 2021 Jan 12;34(2):108630. doi: 10.1016/j.celrep.2020.108630. Epub 2020 Dec 26.


The severe acute respiratory coronavirus 2 (SARS-CoV-2) spike (S) protein is the target of vaccine design efforts to end the coronavirus disease 2019 (COVID-19) pandemic. Despite a low mutation rate, isolates with the D614G substitution in the S protein appeared early during the pandemic and are now the dominant form worldwide. Here, we explore S conformational changes and the effects of the D614G mutation on a soluble S ectodomain construct. Cryoelectron microscopy (cryo-EM) structures reveal altered receptor binding domain (RBD) disposition; antigenicity and proteolysis experiments reveal structural changes and enhanced furin cleavage efficiency of the G614 variant. Furthermore, furin cleavage alters the up/down ratio of the RBDs in the G614 S ectodomain, demonstrating an allosteric effect on RBD positioning triggered by changes in the SD2 region, which harbors residue 614 and the furin cleavage site. Our results elucidate SARS-CoV-2 S conformational landscape and allostery and have implications for vaccine design.

Keywords: 2P; COVID-19; D614G; SARS-CoV-2; allostery; cryo-EM; furin cleavage; spike.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19 / pathology
  • COVID-19 / virology
  • Cryoelectron Microscopy
  • Humans
  • Immunogenicity, Vaccine
  • Molecular Dynamics Simulation
  • Mutation
  • Peptide Hydrolases / metabolism*
  • Protein Domains
  • Protein Stability
  • Protein Structure, Quaternary
  • Protein Subunits / metabolism
  • Proteolysis
  • SARS-CoV-2 / isolation & purification
  • SARS-CoV-2 / metabolism*
  • Spike Glycoprotein, Coronavirus / chemistry
  • Spike Glycoprotein, Coronavirus / genetics
  • Spike Glycoprotein, Coronavirus / metabolism*


  • Protein Subunits
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2
  • Peptide Hydrolases