Fig. 6.

The electrostatic energies contributed by each of the key residues responsible for the decreases of the binding affinity caused by the E484K mutation for the complex systems formed by RBD with the neutralizing antibody BD23 (a), the nanobody H11-D4 (b), the neutralizing antibody BD368-2(c), the nanobody Nb20 (d), the nanobody MR17-K99Y (e) and the neutralizing antibody S2M11 (f), respectively. In these figures, the residue E484K is located on RBD, and the other residues are from the antibodies/nanobodies, which dominantly contribute to the decreases of the binding affinity.