FIG 3.
SPR analysis of ACE2 variants binding viral spike proteins. (A and B) The N-terminal peptidase domain of each human ACE2 (residues Met1-Asp615) variant (A), SARS-CoV-2 RBD (residues Thr333-Pro527), SARS-CoV RBD (residues Arg306-Leu515), or NL63-CoV RBD (residues Gln481-Ile616) (B) were expressed and purified as described in Materials and Methods. The purified proteins were analyzed by SDS-PAGE with Coomassie blue staining. (C) Affinity of ACE2 SNVs for coronavirus spike proteins. Dissociation constant (Kd) values were determined by SPR and are presented as a heatmap according to the indicated color legend. This experiment was independently repeated three times with similar results.