Recombinant SARS-CoV-2 Spike protein S1 subunit, encompassing amino acids 16-685. This protein corresponds to SARS-CoV-2 Variant B.1.1.7, also known as variant Alpha, originally identified in the United Kingdom. It contains mutations N501Y, A570D, D614G, P681H, and deletions 69-70HV and 144Y. The construct also contains a C-terminal Avi-Tag™ followed by a C-terminal His-tag (6xHis) . The recombinant protein was affinity purified.