Recombinant SARS-CoV-2 (Omicron variant) Spike glycoprotein S1. Relative to Wuhan-Hu-1 the protein contains following amino acid changes: A67V, H69del, V70del, T95I, G142D, V143del, Y144del, Y145del, N211del, L212I, ins214EPE, G339D, S371L, S373P, S375F, K417N, N440K, G446S, S477N, T478K, E484A, Q493R, G496S, Q498R, N501Y, Y505H, T547K, D614G, H655Y.