Fig. 3

Evolutionary conservation of SARS-CoV receptor ACE protein. a Amino acid sequence alignment (Blast E-value = 0.003, max cluster distance = 0.4) was performed with COBALT (https://www.ncbi.nlm.nih.gov/tools/cobalt/cobalt.cgi?LINK_LOC=BlastHomeLink) using protein sequences for ACE in fruit fly (Drosophila melanogaster; Uniprot ID: NP_001285915), water flea (Daphnia pulex; E9GU43), water flea order (D. pulex; A0A162PAD4), body louse (Pediculus humanus corporis; E0VAB8), deer tick (Ixodes scapularis; A0A4D5RPS5), Chinese horseshoe bat (Rhinolophus sinicus; E2DHI7) and human ACE2 (Homo sapiens; Q9BYF1). Conserved regions are highlighted in red. b Prediction of fruit fly ACE and human ACE2 proteins secondary structure using CFSSP: Chou & Fasman Secondary Structure Prediction Server (http://www.biogem.org/tool/chou-fasman/index.php). c Amino acids K31, E35, D38, M82 and K353 identified as involved in the interface between SARS-CoV and human ACE2 [16]. d Slanted cladogram of ACE protein sequences using the Neighbor joining algorithm (max seq difference = 0.85, distance = Grishin protein) at NCBI tree viewer (https://www.ncbi.nlm.nih.gov/tools/treeviewer/)