FIGURE 1.

Structure of the Spike glycoprotein. The Spike glycoprotein, S1 and S2 domains, in the absence of glycan residues and lipid bilayer. The S1 domain is shown in pink and S2 in iceblue color. The top view of the protein shows a triangular arrangement of the S1 domain. Below the structure is a schematic showing the location of important regions on the S1 and S2 domains of the protein. The abbreviations in the S1 and S2 domains are: – NTD, N-terminal domain; RBD, receptor binding domain; RBM, receptor binding motif. The starting and ending residues are numbered.