Structures of SARS-CoV-2 spike protein alert noteworthy sites for the potential approaching variants

• Deletion of residues 156–157 warps the neighboring beta-sheet and leads NTD and RBD to shift. • T859N stabilizes the packing of the 630 loop motif to make RBD standing transition more difficult. • The overall structures of the closed state S complex from different variants resemble each other. • Mutations in FPPR may affect the overall structure of the trimeric spike protein.