Receptor utilization of angiotensin‐converting enzyme 2 (ACE2) indicates a narrower host range of SARS‐CoV‐2 than that of SARS‐CoV

Abstract

Summary 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 are most likely originated 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. Nevertheless, the actually susceptibility of these animals to the coronaviruses should be further verified by in‐vivo studies. 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 20 th and 42 nd amino acid residues that might determine the different receptor utilization of SARS‐CoV, SARS‐CoV‐2 and pangolin CoV. Our studies enhance the understanding of receptor utilization of pandemic coronaviruses, potentially contributing to the virus tracing, intermediate host screening and epidemic prevention for pathogenic coronaviruses.

Serine 477 plays a crucial role in the interaction of the SARS-CoV-2 spike protein with the human receptor ACE2.

“…1b) with reported substitutions to G(2) I(7) N(3400) R(2) T(2) X (20). Deep mutational scanning of the RBD has shown that a mutation at S477 has a potential to affect the stability of the RBD as well as its binding to the ACE2 13 , whereas the structural effect of residue S477 in context of intra-RBD interactions is lesser understood while it is reported that the residues S477 and T478 in SARS-CoV-2 are responsible for specific and efficient interactions with hACE2 and provide an edge over SARS-CoV 14 . Therefore, we investigate the structural contribution of residue S477 in the RBD in order to understand its role inhACE2 binding.…”

Serine 477 plays a crucial role in the interaction of the SARS-CoV-2 spike protein with the human receptor ACE2.

“…1b) with reported substitutions to G(2) I 7N(3400) R(2) T(2) X (20). Deep mutational scanning of the RBD has shown that a mutation at S477 has a potential to affect the stability of the RBD as well as its binding to the ACE2 13 , whereas the structural effect of residue S477 in context of intra-RBD interactions is lesser understood while it is reported that the residues S477 and T478 in SARS-CoV-2 are responsible for specific and efficient interactions with hACE2 and provide an edge over SARS-CoV 14 . Therefore, we investigate the structural contribution of residue S477 in the RBD in order to understand its role inhACE2 binding.…”

Variations in cell-surface ACE2 levels alter direct binding of SARS-CoV-2 Spike protein and viral infectivity: Implications for measuring Spike protein interactions with animal ACE2 orthologs

“…Several studies to date have expressed different ACE2 orthologs on cells to measure the potential for SARS-CoV-2 infectivity. The results have shown some consistent patterns, such as the inability of Mus musculus ACE2 to interact with SARS-CoV-2 [2,24,26,32], (with the exception of mouse cells from the cornea [43]) or the relatively high infectivity afforded by pangolin ACE2 [6,26,28,29]. Results from other orthologs are more inconsistent.…”

“…in silico models that predict which orthologs would be likely to bind S-protein based upon amino acid residues known to interact with S-protein [4,9,[15][16][17][18][19][20][21][22][23][24][25], 2.) in vitro cell-based studies where viral infectivity of cells from different animals or cell-lines genetically modified to express different ACE2 orthologs are examined for interactions with S-protein (or its RBD) or infection with the virus or S-protein expressing pseudovirus [2,6,11,[26][27][28][29][30], 3.) and biochemical studies measuring the binding of S-protein with different ACE2 proteins [31,32].…”