Figure Legends
Fig. 1 Key mutations of variants B.1.351 and P1 fall on the interface between the RBD and ACE2. (left) S monomer (purple ribbon) bound to ACE2 ectodomain (orange surface). In detail, the positions of residues K417, E484, and N501 (blue sticks) are highlighted. Mutations E484K and N501K occur on the RBM segments (dark purple ribbon), while K417N occurs on helix α4 of RBD. From PDB files 6ACG and 6M0J.
Fig. 2 Binding kinetics of RBDWT (A), RBDTRIP (B), RBDN501Y (C), RBDE484K (D), and RBDK417N (E) to hACE2. In all assays, both association and dissociation were performed in 300 s. The resulting kon and koff values from each condition are compared in panel (F).
Fig. 3 Sera of COVID-19 convalescent patients bind less to RBDWT and mutated RBDs (RBDTRIP, RBDN501Y, RBDE484K, and RBDK417N). A) Binding of sera from 12 COVID-19 convalescent patients and one COVID negative individual to RBDWT and mutated RBDs was determined by ELISA. Endpoint titres (EPT) (dilution factor) individuals are shown as dots. Direct binding of sera to RBDWT and mutated RBDs (B) and competitive inhibition of ACE2-mFc interaction to RBDWTand mutated RBD (C) were assessed by BLI. The same sera (dilution 1:20) for each individual was usual. p≤0.05 (*), p≤0.01 (**), p≤0.005 (***), p≤0.001 (****).