Identification of ACE2 mutations that modulate SARS-CoV-2 spike binding across multiple mammalian species

bioRxiv. 2021 Mar 17;2021.03.16.435705. doi: 10.1101/2021.03.16.435705. Preprint


Understanding how SARS-CoV-2 interacts with different mammalian angiotensin-converting enzyme II (ACE2) cell entry receptors will help elucidate determinants of intra- and cross-species virus transmission, facilitate development of effective new vaccines for both humans and livestock animals, and guide livestock farming and coronavirus screening procedures to ensure food supply security. In this work we applied laboratory directed evolution to several mammalian ACE2s with the goal of identifying conserved ACE2 mutations that increase spike binding affinity across multiple species. We found the Gln42Leu mutation increased ACE2-spike binding for human as well as four of four other mammalian ACE2s, while the Leu79Ile mutation had a similar effect for human and three of three mammalian ACE2 orthologs. These results are especially notable given the residues' high levels of representation, i.e, 83% for Gln42 and 56% for Leu79, among annotated mammalian ACE2s. We also found that substitutions at ACE2 position 34, which is relatively variable across mammalian ACE2s, increased binding for multiple ACE2 orthologs. Taken together, these results speak strongly to the plausibility of SARS-CoV-2 strains with increased ability to cross species transmission barriers. Our results can guide further computational and experimental studies to develop biomedical technologies and animal husbandry practices that help protect both humans and livestock from existing and future SARS-CoV-2 variants.

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