Fig 1.

Residues under positive selection in bat ACE2 correspond to human ACE2 residues that interact with the SARS-CoV spike. (a) Six residues under positive selection (red) in bat ACE2 map to the SARS-CoV-binding surface (orange and red) of human ACE2 (green) and are in direct contact with the SARS-CoV spike (gray) in a cocrystal structure (PDB 2AJF) (17). (b) Bat species used in the ACE2 analysis and the amino acids encoded at the six residue positions that directly contact the SARS-CoV spike and are evolving under positive selection. Bat polymorphisms have been reported at some of these positions (11), and a human polymorphism is found at one of them. (c) Detailed view of the side chains of five of these residues under positive selection (red) in ACE2 (green), along with the side chains of cognate contacts in the SARS-CoV spike (light gray). (d) Cocrystal structures have been solved for human ACE2 in complex with the spike proteins of both SARS-CoV (17) and NL63-CoV (39). ACE2 residues that mediate contact with each virus are indicated. Residues under positive selection in bat ACE2 are indicated in red.