Fig. 1

The palmitoylation levels of S protein and its mutants measured by ABE assays. a Multiple amino acid sequence alignments of the endodomains (1234–1273 aa) of SARS-CoV-2 S protein and its eleven mutants. The dark spots indicate amino acids on the last line. The small letter “a” indicates that the cysteine residue was replaced with an alanine residue. SC10A represents that all ten cysteine residues in the endodomain were changed to alanine residues. SA1235C ~ SA1254C represent that only one cysteine residue in the endodomain was reserved and the other nine cysteine residues were changed to alanine residues. b The palmitoylation levels of S protein and its mutant SC10A. HEK293T cells were transfected with plasmid expressing S-HA or SC10A-HA for 48 h. The palmitoylation levels of S and SC10A were measured by ABE assays and the cells were then immunoblotted with streptavidin-HRP and anti-HA antibody. M: protein molecular mass marker. C The palmitoylation levels of ten mutants SA1235C ~ SA1254C. HEK293T cells were transfected with ten mutant plasmids expressing SA1235C ~ SA1254C for 48 h. The palmitoylation levels of the ten mutants were measured by ABE assays