Sarbecoviruses with long RBMs achieve broad ACE2 tropism, whereas those with single deletions exhibit narrower tropism and double deletions completely lose ACE2 usage.
Sarbecovirus RBM indels and specific residues dictate multi-species ACE2 adaptiveness, providing insights into the mechanisms governing ACE2 usage and spillover risks.
Our comprehensive understanding of the multi-species ACE2 adaptiveness of sarbecoviruses remains elusive, particularly for those with various receptor binding motif (RBM) insertions/deletions (indels). Here, we analyzed RBM sequences from 268 sarbecoviruses categorized into four RBM indel types. We examined the ability of 20 representative sarbecovirus Spike glycoproteins (S) and derivatives in utilizing ACE2 from various bats and several other mammalian species. We reveal that sarbecoviruses with long RBMs (type-I) can achieve broad ACE2 tropism, whereas viruses with single deletions in Region 1 (type-II) or Region 2 (type-III) exhibit narrower ACE2 tropism. Sarbecoviruses with double region deletions (type-IV) completely lost ACE2 usage, which is restricted by clade-specific residues within and outside RBM. Lastly, we propose the evolution of sarbecovirus RBM indels and illustrate how loop lengths, disulfide, and residue determinants shape multi-species ACE2 adaptiveness. This study provides profound insights into the mechanisms governing ACE2 usage and spillover risks of sarbecoviruses. To understand why sarbecoviruses display different abilities in using ACE2 from various species, the authors investigate the ACE2 orthologue tropism of these viruses and elucidate how they have evolved along three distinct paths through RBD indels and specific residues.
Si et al. (Mon,) conducted a other in Sarbecovirus ACE2 adaptiveness. Receptor binding motif (RBM) insertions/deletions (indels) was evaluated on ACE2 tropism and usage. Sarbecoviruses with long RBMs achieve broad ACE2 tropism, whereas those with single deletions exhibit narrower tropism and double deletions completely lose ACE2 usage.