Strong evolutionary convergence of receptor-binding protein spike between COVID-19 and SARS-related coronaviruses

Yonghua Wu

Given the strong evolutionary convergence of RBD of spike protein between the two clades, COVID-19related CoV and SARS-related CoV, the coronaviruses of the two clades may have more likely adapted to similar or the same receptor. To date, 2019-nCoV and SARS-CoV have been known to be capable of using the ACE2 receptor in human host 5,6,9,10 , but the receptors of their phylogenetic relatives from the two clades, COVID-19-related CoV and SARS-related CoV, are less clear 4,5,36,37 . Regarding the bat SARSlike CoV, Rs4231 and Rs7327 are known to be able to use human ACE2 receptor 37 , while WIV16 is capable of using the ACE2 receptor from humans, civets and Chinese horseshoe bats (Rhinolophus sinicus) 4 . The receptors of Rs9401, BtRs-BetaCoV/YN2018B, and BatCoV RaTG13 remain to be explored. Further studies on the receptors of these bat SARS-like CoVs in their natural reservoirs are badly needed to determine whether ACE2 or other candidates, if any, represent their shared cell receptor, leading to their strong evolutionary convergence of spike protein.