Recombinant SARS-CoV-2 Spike protein S1 subunit, encompassing amino acids 16-685. This protein corresponds to SARS-CoV2 variant B.1.429, also known as variant Epsilon originally discovered in California (USA), and contains mutations W152C, L452R and D614G. The construct also contains a C-terminal Avi-Tag™ followed by a His-tag (6xHis). The protein was enzymatically biotinylated using the Avi-Tag™ and affinity purified.