Fig. 2

Alignment and electrostatic surface potential analysis of key amino acids residues of AXL. A Sequence alignment analysis of the interface binding between ACE2 and S of SARS-CoV-2 from ferrets (GenBank accession no. XP_004776133.1), minks (GenBank accession no. XP_044113292.1), bovines (GenBank accession no. XP_024834863.1), humans (GenBank accession no. NP_068713.2), rhesus monkeys (GenBank accession no. XP_028695606.1), hamsters (GenBank accession no. XP_035292416.1), and mice (GenBank accession no. XP_006540052.1). The ALX residues at positions 61, 68, 85, 113, 115, and 116 are marked with blue triangles. B Electrostatic surface potential diagram of AXLs in different species. The structural superposition of the AXL region 29–127 from cattle (green), minks (brown), ferrets (cyan), mice (gray), hamsters (pink), humans (khaki), and rhesus monkeys (blue) is in the center. The homology models of human AXL (PDBID 4yfg) were used to compare the AXL structures of cattle, minks, ferrets, mice, hamsters, and rhesus monkeys. The tertiary structure was predicted using SWISS-MODEL. The yellow sticks highlight the six key differential resides of AXL binding with S of SARS-CoV-2. The details are circled using a dashed line in each electrostatic surface potential map. The electrostatic potential color range is –/ + 5