Fig. 3: Mutations in the omicron spike introduce new inter-domain and inter-subunit interactions that may stabilize its open conformation.

a Structural distribution of all of the mutations in the omicron spike ectodomain. The omicron open spike is colored in the same way as Fig. 1c. All of the mutations are shown in the red sphere and labeled with their residue numbers as in the omicron spike (the corresponding residue numbers in the prototypic spike are shown in parentheses). Three residues that introduce new inter-domain and inter-subunit interactions are highlighted in red. b–d New inter-domain and inter-subunit interactions in the omicron open spike are mediated by three new mutations. The omicron open spike is colored in the same way as Fig. 2a. The dashed lines represent salt bridges and hydrogen bonds.