Fig. 1: Overall structures of the RaTG13 and PCoV_GX spike glycoproteins.

a Overall structures of the RaTG13 and PCoV_GX spike glycoproteins shown in side view (upper panel) and top view (lower panel). The domains were painted with colors shown in b and c. The trigonal axes are shown as black dashed lines. Visible segments of each monomer are labeled accordingly. The cap and stalk parts are partitioned by gray dashed lines. b Schematic representation of the RaTG13 spike monomer structural domains. The domains of RaTG13 are shown as boxes with the width related to the length of the amino acid sequence. The start and end amino acids of each segment are labeled. The position of the S1/S2 and S2’ cleavage sites are indicated by scissors. NTD, N-terminal domain; CTD, C-terminal domain; SD1, subdomain 1; SD2, subdomain 2; UH, upstream helix; FP, fusion peptide; CR, connecting region; HR1, heptad repeat 1; CH, central helix; BH, β-hairpin; SD3, subdomain 3. c Schematic representation of the PCoV_GX spike monomer structural domains. The abbreviations of elements are the same as in b. d Cartoon diagrams depicting three orientations of the spike monomer colored as in b and c. As the RaTG13 and PCoV_GX spike monomers have extremely similar structures, thus only the RaTG13 spike monomer was used to show the detailed architecture.