N501Y mutation imparts cross-species transmission of SARS-CoV-2 to mice by enhancing receptor binding

According to the World Health Organization (WHO), as of March 8, 2021, the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had infected more than 116 million patients with coronavirus disease 2019 (COVID-19) ( https://covid19.who.int ). The high infectivity of SARS-CoV-2 is largely attributable to the unique sequence composition of its spike (S) glycoprotein. During the process of viral infection, this glycoprotein can be processed into two fragments. The N terminal S1 fragment is responsible for receptor binding, and the C terminal S2 fragment promotes membrane fusion. 1 SARS-CoV-2 is an RNA virus, and it has undergone frequent mutations, which have produced several variants over the past year. On top of this, the D614G mutation in the S glycoprotein has been shown to enhance viral infectivity. 2 , 3 However, the functional implications of most mutations are largely speculative and not clear.