Description：Recombinant COVID-19 S-trimer Protein (Omicron, BA.2) is produced by our mammalian expression system and the target gene encoding Ser13-Gln1208 is expressed with a 6His tag at the C-terminus. T19I, LPPA24S, G142D, V213G, G339D, S371F, S373P, S375F, T376A, D405N, R408S, K417N, N440K, S477N, T478K, E484A, Q493R, Q498R, N501Y, Y505H, D614G, H655Y, N679K, P681H, N764K, D796Y, Q954H and N969K mutations were identified in the COVID-19 variant (known as BA.2 lineage) which emerged in the United Kindom. Six proline substitutions and furin cleavage site substitutions are introduced to stabilize the trimeric prefusion state of Recombinant COVID-19 S protein and abolish the furin cleavage site, respectively.Form：Liquid in a 0.2 μm filtered solution of PBS, pH 7.4.Alternative Names：SARS-CoV-2 RBD Protein; SARS-CoV-2 Spike RBD Protein; SARS-CoV-2 S Protein RBD Entrez Gene (Human)： 43740568; SwissProt (Human)： P0DTC2; Purity：Greater than 95% as determined by reducing SDS-PAGE.Directions for Use：Please minimize freeze-thaw cycles.Quality Control：Endotoxin: Less than 0.1 ng/µg (1 IEU/µg) as determined by LAL test.Storage/Stability：Store it at -20°C to -80°C for one year. It is recommended that the protein be aliquoted for optimal storage. Avoid repeated freeze-thaw cycles.

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  Greater than 95% as determined by reducing SDS-PAGE.
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  Loaded Human ACE-2 on Protein A Biosensor, can bind Recombinant COVID-19 S-trimer Protein (Omicron, BA.2) with an affinity constant of 0.07 nM as determined in bioactivity assay.
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  Loaded Anti-COVID-19 S1 mAb on Protein A Biosensor, can bind Recombinant COVID-19 S-trimer Protein (Omicron, BA.2) with an affinity constant of 4.87 nM as determined in bioactivity assay.