Recombinant Protein;500UG;SARS-CoV-2 S protein trimer, His Tag (SPN-C52Hk) is expressed from human 293 cells (HEK293). It contains AA Val 16 - Pro 1213 (Accession # QHD43416.1). The recombinant protein is expressed from human 293 cells (HEK293) with T4 fibritin trimerization motif and a polyhistidine tag at the C-terminus. Proline substitutions (F817P/ A892P/ A899P/ A942P/ K986P/ V987P) and alanine substitutions (R683A and R685A) are introduced to stabilize the trimeric prefusion state of SARS-CoV-2 S protein and abolish the furin cleavage site, respectively. L18F/ D80A/ D215G/ LAL242-244del/ R246I/ K417N/ E484K/ N501Y/ D614G/ A701Vmutations were identified on the spike protein in the SARS-CoV-2 variant (known as B.1.351 or 20C/501Y.V2) which emerged in South Africa.;This protein carries a polyhistidine tag at the C-terminus. The protein has a calculated MW of 137.6 kDa. The protein migrates as 170-200 kDa under reducing (R) condition (SDS-PAGE) due to glycosylation.;Immobilized SARS-C