Fig. 3

Alignment and surface potential analysis of crucial amino acids in ACE2 proteins. (A) Comparative analysis of the residues of ACE2s at the interface binding to the spike protein of SARS-CoV-2 from human (GenBank accession no. NP_001358344.1), rhesus (GenBank accession no. NP_001129168.1), hamster (GenBank accession no. XP_003503283.1), mouse (GenBank accession no. NP_001123985.1), ferret (GenBank accession no. NP_001297119.1), mink (GenBank accession no. XP_044091953), and chickens (GenBank accession no. XP_040517014.1). The ACE2 residues at positions 368, 380, 386, 502, and 507 are marked in blue triangles. (B) Surface potential diagram of interface zone of ACE2s. The structural superposition of the ACE2 region 366–520 from human (yellow, PDB code 6m18), rhesus (violet), hamster (purple), mouse (gray, UniProt entry Q0093), ferret (cyan), mink (red), and chickens (green). The ACE2 structures of chickens, rhesus, hamster, ferret, and mink were modeled using the homology models of human ACE2 (PDB code 6m18) as the templates by SWISS-MODEL (https://swis-smodel.expasy.org/). The five key differential residues of ACE2 interacting with the spike protein of SARS-CoV-2 are represented by yellow sticks in the structural superposition, the black dash line indicates the key residues in the potential surface diagram. The electrostatic potential color range is -/+5