Figure legends
Figure 1. Validation of pseudovirues preparation and ACE2 expression. (A) Western blot Detection of spike proteins of SARS-CoV-BJ01, SARS-CoV-2 and Pangolin CoV in the package cells using an antibody against the HA tag conjugated to the viral spike proteins. β-actin was detected as the loading control. (B) Alignment of the amino acid sequences of the receptor binding motifs (RBM) of SARS-CoV, SARS CoV-2 and Pangolin CoV spike proteins. (C) Detection of different ACE2 orthologs in HeLa cells after transfecting the corresponding plasmids using an antibody against the 6XHis tag conjugated to the ACE2 proteins. β-actin was detected as the loading control.
Figure 2. Entry efficiency of SARS-CoV-BJ01, SARS-CoV-2 and Pangolin CoVpseudoviruses intoACE2-expressing cells.HeLa cells expressing different ACE2 orthologs were infected by SARS-CoV, SARS-CoV-2 or Pangolin CoV pseudoviruses. At 48 h post infection, pseudovirus entry efficiency was determined by measuring luciferase activity in cell lysates. The results were presented as the mean relative luminescence units and the error bars indicated the standard deviations (n = 9).
Figure 3. Phylogenetic analysis of the 20 ACE2 orthologs and the key amino acid residues for SARS-CoV-2 utilization. (A) The phylogenetic tree was constructed on the whole aa sequences of ACE2s using NJ method by MEGA7 with 1,000 bootstrap replicates (left panel) and the amino acids on the 9 critical sites predicted previously were listed (right panel). (B) The structure of the complex of SARS-CoV-2 spike and human ACE2 was adapted from Protein Data Bank (PDB ID: 6VW1). S477, T478 and Q498 of SARS-CoV-2 spike were labelled in green, blue and cyan, respectively. T20 and Q42 were labelled in red and yellow, respectively.