Fig. 1

Schematic overview of the S proteins from the SARS-CoV-2 variants in this study. a The indicated domains and elements, including signal peptide (SP), N-terminal domain (NTD), receptor binding domain (RBD), transmembrane domain (TM) and cytoplasmic domain (CPD), are marked. All the mutations found in the California variant (B.1.429), UK variant (B.1.1.7), and South Africa variant (B.1.351) were shown. All the spike, including wildtype and single or full-set mutations of variants were constructed to generate SARS-CoV-2 pseudovirus. To enhance the packaging efficiency, 18 amino acids at C terminal of spike were depleted. b The location of the mutations in the context of the trimer spike protein domain. 3D trimer structure of SARS-CoV-2 S protein at closed state (PDB ID: 7DDD) was generated using SwissPdb viewer. Three SARS-CoV-2 S monomers are shown as ribbon diagram in green, yellow and blue colors. The mutated residues are shown as space filling spheres in different colors to distinguish the different mutations. The mutations are labelled only in one of the monomers. Red triangle in B.1.1.7 variant depicts approximate location of P681H, which was not included in the model. c Relative infectivity of VSVΔG-based pseudovirus bearing S of SARS-CoV-2 variants was tested on HEK293T-hACE2 cells. Luciferase activity was measured at 48 h postinfection