Phylogenetic tree of spike proteins reveals major groups of coronaviruses.
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Furin cleavage sites at spike S1/S2 are common in coronaviruses.
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Furin cleavage sites at spike S1/S2 naturally occurred independently for multiple times in coronaviruses.
Abstract
The spike protein is a focused target of COVID-19, a pandemic caused by SARS-CoV-2. A 12-nt insertion at S1/S2 in the spike coding sequence yields a furin cleavage site, which raised controversy views on origin of the virus. Here we analyzed the phylogenetic relationships of coronavirus spike proteins and mapped furin recognition motif on the tree. Furin cleavage sites occurred independently for multiple times in the evolution of the coronavirus family, supporting the natural occurring hypothesis of SARS-CoV-2.
