Comparative ACE2 variation and primate COVID-19 risk

Amanda D. Melin; Mareike C. Janiak; Frank Marrone; Paramjit S. Arora; James P. Higham

Critical residues are defined as those that upon mutation to alanine decrease the binding energy by a threshold value ΔΔGbind ≥1.0 kcal/mol. Nine residues involved in the ACE2-RBD complex met this criterion. There was large congruence in the sites identified by alanine-scanning with those highlighted by other methods. Five of the sites we identified overlap with those that were implicated by cryo EM 14 , which also identified an additional three sites as important. We chose to analyze amino acid variation in the 9 ACE2 sites we identified through alanine scanning, and the additional 3 sites identified by structural analyses 14-17 for a total of 12 critical sites (Supple. Table S2 ). All computational alanine scanning mutagenesis analyses were performed using Rosetta software 32 . The alanine mutagenesis approach has been extensively evaluated and used to analyze PPIs and design their inhibitors, including by members of the present authorship 33, 34 .