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

S. Gobeil, K. Janowska, Shana McDowell, K. Mansouri, R. Parks, K. Manne, V. Stalls, Megan F. Kopp, R. Henderson, R. Edwards, B. Haynes, P. Acharya

Cell Reports, 2020

The SARS-CoV-2 spike (S) protein is the target of vaccine design efforts to end the 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 spike conformational changes and the effects of the D614G mutation on a soluble S ectodomain construct. Cryo-EM structures reveal altered 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 Receptor Binding Domains (RBD) in the G614 S ectodomain, demonstrating an allosteric effect on RBD positioning triggered by changes in the SD2 region, that harbors residue 614 and the furin cleavage site. Our results elucidate SARS-CoV-2 spike conformational landscape and allostery, and have implications for vaccine design.

Cited by 50 publications.

Field of study: Medicine

10.1016/j.celrep.2020.108630