Fig. 7.

Natural variants of SARS-CoV-2 spike protein. Natural variants are highlighted in red, with sphere sizes corresponding to the frequency of each variant as reported in reference [72]. For clarity, only one protomer is represented in tubes and the other two are shown in a white surface (PDB ID: 6VSB⁴) [46]. (A) For the S1 domain, RBD (in an up conformation) and NTD are highlighted in yellow and green tubes, respectively, The S1 SD domains and S2 shown in light blue and grey, respectively. The rest of the S trimer is shown in a white surface representation. (B) Natural variants on the RBD are highlighted. (C) The major natural variant D614G is highlighted in red. D614 (red) can form a hydrogen bond with T859 (white) in an adjacent protomer, but G614 cannot form this H bond.