Structural features of the SARS-CoV-2 spike (S) protein. (a) Trimeric structure (each S protein has a distinct surface colour, ‘blue’, ‘yellow’ and ‘purple’). (b) Ribbon representation of ‘blue’ S protein in the trimer (α-helix, red; β-strand, blue; coil, grey). (c) Surface structure of the ‘blue’ S protein isolated from the trimer. (d) Ribbon structure of the ‘blue’ S protein. (e) Zoom on the N-terminal domain (NTD) of the ‘blue’ S protein. (f,g) Molecular model of a minimal NTD obtained with Hyperchem [ribbon in representation in (f), surface rendering in (g)]. (h) Highlighting of the amino acid residues of the NTD that could belong to a potential ganglioside-binding domain.