Figure 6.

The potential electrostatic screened energy U is estimated for charged RBD and ACE2 as a function of a distance d. Point model and screened Coulomb energy U=Q₁Q₂Exp(-d/L_D)/(4Πε₀εd) was assumed, with Q₁= +7 [e] or Q₁= +10 [e], Q₂= −28 [e], ε= 80, and Debye screening length L_D= 0.7 nm. The ε₀ is the dielectric permittivity of a vacuum. Two curves represent different RBD charges, referential (+7 [e]) and after positive charge mutation (+10 [e]), as in virus variant Zeta A.V1. The arrow indicates the direction of attraction of the positive electric charge.