Figure 3.

Cryo-ET and Subtomogram Averaging of SARS-CoV-2 Postfusion Spike

(A) Tomographic slice of inactivated SARS-CoV-2 viruses.

(B) Enlarged view of the boxed region in (A). Viral spikes are indicated by yellow arrowheads.

(C) Segmentation of a representative virus particle, showing the prefusion spikes in cyan, postfusion spikes in orange, membrane in light gray, and ribonucleoprotein and RNA genome complex in blue. The distribution of prefusion and postfusion spikes and the 95% confidence interval are listed below.

(D) Density map of the postfusion SARS-CoV-2 spike fitted with a SARS-CoV model (PDB: 6M3W) (Fan et al., 2020). The unmodeled density at the bottom could account for 224 residues not resolved in PDB: 6M3W. Two glycan sites are labeled. Right side shows sectional views at the positions marked by the blue dashed lines. Scale bars, 50 nm in (A), 20 nm in (B).