Receptor utilization of angiotensin converting enzyme 2 (ACE2) indicates
a narrower host range of SARS-CoV-2 than that of SARS-CoV
Abstract
Coronavirus (CoV) pandemics have become a huge threat to the public
health worldwide in the recent decades. Typically, severe acute
respiratory syndrome CoV (SARS-CoV) caused SARS pandemic in 2003 and
SARS-CoV-2 caused the ongoing COVID-19 pandemic. Both viruses have been
reported to originate from bats. Thus, direct or indirect interspecies
transmission from bats to humans is required for the viruses to cause
pandemics. Receptor utilization is a key factor determining the host
range of viruses which is critical to the interspecies transmission.
Angiotensin converting enzyme 2 (ACE2) is the receptor of both SARS-CoV
and SARS-CoV-2, but only ACE2s of certain animals can be utilized by the
viruses. Here, we employed pseudovirus cell-entry assay to evaluate the
receptor-utilizing capability of ACE2s of 20 animals by the two viruses
and found that SARS-CoV-2 utilized less ACE2s than SARS-CoV, indicating
a narrower host range of SARS-CoV-2. Especially, SARS-CoV-2 tended not
to use murine or non-mammal ACE2s. Meanwhile, pangolin CoV, another
SARS-related coronavirus highly homologous to SARS-CoV-2 in its genome,
yet showed similar ACE2 utilization profile with SARS-CoV rather than
SARS-CoV-2. To clarify the mechanism underlying the receptor
utilization, we compared the amino acid sequences of the 20 ACE2s and
found 5 amino acid residues potentially critical for ACE2 utilization,
including the N-terminal 20th and 42nd amino acids that may determine
the different receptor utilization of SARS-CoV, SARS-CoV-2 and pangolin
CoV. Our studies promote the understanding of receptor utilization of
pandemic coronaviruses, potentially contributing to the virus tracing,
intermediate host screening and epidemic prevention for pathogenic
coronaviruses.