Recombinant SARS-CoV-2 S protein RBD Protein is produced by our Mammalian expression system and the target gene encoding Arg319-Phe541 (G339D, S371L, S373P, S375F, K417N, N440K, G446S, S477N, T478K, E484A, Q493R, G496S, Q498R, N501Y, Y505H) is expressed with a 6His tag at the C-terminus. G339D, S371L, S373P, S375F, K417N, N440K, G446S, S477N, T478K, E484A, Q493R, G496S, Q498R, N501Y and Y505H mutations were identified in the SARS-CoV-2 variant (known as Omicron/B.1.1.529 lineage) which emerged in South Africa.