Fig. 4.

(A) Display of common hydrogen-bonding interactions present in all the three RBD-ACE2 complexes. Protein is rendered in cartoon mode and residues forming hydrogen bonding interactions are shown in stick mode. Unique interactions present in the wild-type RBD-ACE2 complex (B), N501Y RBD-ACE2 complex (C), and E484K RBD-ACE2 complex (D) are shown. RBD and ACE2 are colored in red and green, respectively. Residues forming hydrogen bonds, π-π, and π-cation interactions are shown in stick mode. Residues involved in electrostatic interactions are shown in the sphere representation. Positive and negatively charged residues are colored in blue and red, respectively. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)