D614G Mutation Alters SARS-CoV-2 Spike Conformation and Enhances Protease Cleavage at the S1/S2 Junction
Sophie M.-C. Gobeil,
Katarzyna Janowska,
Shana McDowell,
Katayoun Mansouri,
Robert Parks,
Kartik Manne,
Victoria Stalls,
Megan F. Kopp,
Rory Henderson,
Robert J. Edwards,
Barton F. Haynes,
Priyamvada Acharya
Affiliations
Sophie M.-C. Gobeil
Duke Human Vaccine Institute, Durham, NC 27710, USA
Katarzyna Janowska
Duke Human Vaccine Institute, Durham, NC 27710, USA
Shana McDowell
Duke Human Vaccine Institute, Durham, NC 27710, USA
Katayoun Mansouri
Duke Human Vaccine Institute, Durham, NC 27710, USA
Robert Parks
Duke Human Vaccine Institute, Durham, NC 27710, USA
Kartik Manne
Duke Human Vaccine Institute, Durham, NC 27710, USA
Victoria Stalls
Duke Human Vaccine Institute, Durham, NC 27710, USA
Megan F. Kopp
Duke Human Vaccine Institute, Durham, NC 27710, USA
Rory Henderson
Duke Human Vaccine Institute, Durham, NC 27710, USA; Department of Medicine, Duke University, Durham, NC 27710, USA
Robert J. Edwards
Duke Human Vaccine Institute, Durham, NC 27710, USA; Department of Medicine, Duke University, Durham, NC 27710, USA
Barton F. Haynes
Duke Human Vaccine Institute, Durham, NC 27710, USA; Department of Medicine, Duke University, Durham, NC 27710, USA; Department of Immunology, Duke University, Durham NC 27710, USA
Priyamvada Acharya
Duke Human Vaccine Institute, Durham, NC 27710, USA; Department of Surgery, Duke University, Durham NC 27710, USA; Corresponding author
Summary: 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.
