Fig. 4.

Ab initio modeling of the loop containing the furin cleavage site in S protein of SARS-CoV-2. Left panel: Heatmap indicating the helical propensity for each residue in a cluster. The clusters i-viii are sorted based on their energy score (most favorable first) and the number in parenthesis indicates the number of structures within a cluster. Residues in the protease cleavage site region are displayed in red. The furin cleavage site is indicated by a red arrowhead. Right panel: The lowest energy model with a helical structure for each cluster is shown. The upper and lower numbers indicate the cluster number and the rank of the model within the cluster, respectively. The red sphere shows the furin cleavage site (Cα of R685).