Spike mutation T403R allows bat coronavirus RaTG13 to use human ACE2

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the cause of the COVID-19 pandemic, most likely emerged from bats. A prerequisite for this devastating zoonosis was the ability of the SARS-CoV-2 Spike (S) glycoprotein to use human angiotensin-converting enzyme 2 (ACE2) for viral entry. Although the S protein of the closest related bat virus, RaTG13, shows high similarity to the SARS-CoV-2 S protein it does not efficiently interact with the human ACE2 receptor. Here, we show that a single T403R mutation allows the RaTG13 S to utilize the human ACE2 receptor for infection of human cells and intestinal organoids. Conversely, mutation of R403T in the SARS-CoV-2 S significantly reduced ACE2-mediated virus infection. The S protein of SARS-CoV-1 that also uses human ACE2 also contains a positive residue (K) at this position, while the S proteins of CoVs utilizing other receptors vary at this location. Our results indicate that the presence of a positively charged amino acid at position 403 in the S protein is critical for efficient utilization of human ACE2. This finding could help to predict the zoonotic potential of animal coronaviruses.

Genomic screening of 16 UK native bat species through conservationist networks uncovers coronaviruses with zoonotic potential

“…Notably, single mutations in sarbecoviral spike proteins have been shown to enable binding of ACE2 from novel host species 48 . Additionally, a single T403R mutation in the RaTG13 spike has been shown to allow the virus to infect human cells 49 , we speculate that the genetic barrier precluding effective hACE2 usage for cellular entry into human cells may be small. This may also be the case for our novel sarbecoviruses, which already share more than half of the SARS-CoV-2 contact residues, and is reflected by the ability of RhGB02 to infect hACE2-overexpressing cells.…”

“…Notably, single mutations of some of the SARS-CoV-2 contact residues in sarbecoviral spike proteins have been shown to enable binding of ACE2 from novel host species and improve binding affinity by greater than fivefold 44 . Additionally, a single T403R mutation in the RaTG13 spike has been shown to allow the virus to infect human cells 53 . Given this, we speculate that the genetic barrier precluding effective hACE2 usage for cellular entry into human cells may be small.…”

Genomic screening of 16 UK native bat species through conservationist networks uncovers coronaviruses with zoonotic potential

“…Notably, single mutations of some of the SARS-CoV-2 contact residues in sarbecoviral spike proteins have been shown to enable binding of ACE2 from novel host species and improve binding affinity by greater than fivefold 43 . In addition, a single T403R mutation in the RaTG13 spike has been shown to allow the virus to infect human cells 52 . Given this, we speculate that the genetic barrier precluding effective hACE2 usage for cellular entry into human cells may be small.…”

There is still no evidence of SARS‐CoV‐2 laboratory origin: Response to Segreto and Deigin (10.1002/bies.202100137)

“…For example, it was shown that a single T403R mutation in RaTG13 spike protein allows this bat coronavirus to utilize the human ACE2 receptor for infection of human cells and intestinal organoids. [ 24 ] Thus, naturally occurring sarbecoviruses can easily change their preference over ACE2 receptors of different hosts. This is further confirmed by the discovery of naturally occurring bat coronaviruses in Laos, which share RBDs highly similar to that of SARS‐CoV‐2.…”