Natural Polymorphisms Are Present in the Furin Cleavage Site of the SARS-CoV-2 Spike Glycoprotein

Yue Xing1,

Xiao Li2,

Xiang Gao3 and

Qunfeng Dong3,4*

1Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX, United States
2Department of Molecular and Cellular Medicine, Texas A&M University, College Station, TX, United States
3Department of Medicine, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States
4Center for Biomedical Informatics, Stritch School of Medicine, Loyola University Chicago, Maywood, IL, United States

The furin cleavage site in the spike glycoprotein of the SARS-CoV-2 coronavirus is considered important for the virus to enter the host cells. By analyzing 45828 SARS-CoV-2 genome sequences, we identified 103 strains of SARS-CoV-2 with various DNA mutations including 18 unique non-synonymous point mutations, one deletion, and six gains of premature stop codon that may affect the furin cleavage site. Our results revealed that the furin cleavage site might not be required for SARS-CoV-2 to enter human cells in vivo. The identified mutants may represent a new subgroup of SARS-CoV-2 coronavirus with reduced tropism and transmissibility as potential live-attenuated vaccine candidates.