Cell lines and plasmids
HEK293T and HeLa cells were obtained from the American Tissue Culture
Collection and cultured in Dulbecco’s modified Eagle medium (DMEM)
(Gibco, USA) supplemented with 10% fetal bovine serum (FBS) in a
humidified 5% CO2 incubator at 37°C.
Full-length SARS-CoV-2 spike (GenBank accession number MN908947.3),
SARS-CoV BJ01 spike (GenBank accession number AY278488.2) and Pangolin
CoV GD1 spike (GISAID accession number: EPI_ISL_410721) were all
synthesized by Sangon and subcloned into the pcDNA3.1 vectors with a
C-terminal HA tag. The cDNAs encoding different ACE2 proteins (Table S1)
were synthesized by Sangon and subcloned into pcDNA3.1 vectors with a
C-terminal His tag. All the plasmids were verified by Sanger sequencing.