Mutations derived from horseshoe bat ACE2 orthologs enhance ACE2-Fc neutralization of SARS-CoV-2

PLoS Pathog. 2021 Apr 9;17(4):e1009501. doi: 10.1371/journal.ppat.1009501. eCollection 2021 Apr.

Abstract

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein mediates infection of cells expressing angiotensin-converting enzyme 2 (ACE2). ACE2 is also the viral receptor of SARS-CoV (SARS-CoV-1), a related coronavirus that emerged in 2002-2003. Horseshoe bats (genus Rhinolophus) are presumed to be the original reservoir of both viruses, and a SARS-like coronavirus, RaTG13, closely related to SARS-CoV-2, has been identified in one horseshoe-bat species. Here we characterize the ability of the S-protein receptor-binding domains (RBDs) of SARS-CoV-1, SARS-CoV-2, pangolin coronavirus (PgCoV), RaTG13, and LyRa11, a bat virus similar to SARS-CoV-1, to bind a range of ACE2 orthologs. We observed that the PgCoV RBD bound human ACE2 at least as efficiently as the SARS-CoV-2 RBD, and that both RBDs bound pangolin ACE2 efficiently. We also observed a high level of variability in binding to closely related horseshoe-bat ACE2 orthologs consistent with the heterogeneity of their RBD-binding regions. However five consensus horseshoe-bat ACE2 residues enhanced ACE2 binding to the SARS-CoV-2 RBD and neutralization of SARS-CoV-2 pseudoviruses by an enzymatically inactive immunoadhesin form of human ACE2 (hACE2-NN-Fc). Two of these mutations impaired neutralization of SARS-CoV-1 pseudoviruses. An hACE2-NN-Fc variant bearing all five mutations neutralized both SARS-CoV-2 pseudovirus and infectious virus more efficiently than wild-type hACE2-NN-Fc. These data suggest that SARS-CoV-1 and -2 originate from distinct bat species, and identify a more potently neutralizing form of soluble ACE2.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Angiotensin-Converting Enzyme 2 / genetics*
  • Angiotensin-Converting Enzyme 2 / immunology*
  • Animals
  • COVID-19 / genetics
  • COVID-19 / immunology*
  • COVID-19 / virology*
  • Chiroptera / genetics
  • Chiroptera / metabolism*
  • Host Specificity / genetics
  • Host Specificity / immunology
  • Humans
  • Models, Molecular
  • Mutation
  • Protein Binding / genetics
  • Protein Binding / physiology
  • Receptors, Virus / metabolism
  • SARS-CoV-2 / genetics*
  • SARS-CoV-2 / immunology
  • Spike Glycoprotein, Coronavirus / metabolism

Substances

  • Receptors, Virus
  • Spike Glycoprotein, Coronavirus
  • Angiotensin-Converting Enzyme 2