21-S2SIN1-TCg-F

SARS-CoV-2 Spike glycoprotein Indian-Kappa (B.1.617.1) variant trimeric ectodomain from mammalian CHO cells, frozen

Description: SARS-CoV-2 recombinant Spike Indian variant (SCoV2-rSκ) glycoprotein ectodomain expressed as secreted trimeric protein in mammalian (hamster) CHO cells. It contains eight mutations in comparison to the reference SARS-CoV-2 Spike protein sequence (UniProtKB accession number: P0DTC2 (SPIKE_SARS2)): T95I, G142D, E154K, L452R, E484Q, D614G, P681R, Q1071H; expressed ectodomain includes amino acids (aa) 1-1208. Whole expression construct includes: full-length SCoV2-S ectodomain (aa 1 – 1208) w/o transmembrane and cytoplasmic aa, furin cleavage site “RRAR” mutated to “GSAS”, C-terminal GSN4 trimerization motif fused to protein sequence, then follows thrombin cleavage site, Strep-tag II and His6-tag. Two mutations (K986P and V987P) were introduced into SCoV2-S sequence to stabilize the trimer in the pre-fusion conformation. SCoV2-rSκ glycoprotein was purified from culture medium under native (non-denaturing) conditions using convenient chromatographic techniques. Then it was dialyzed against PBS, adjusted to 1.0 mg/ml concentration, filter-sterilized, aliquoted and frozen for storage.

Form: Frozen liquid in PBS (pH 7.4).

Storage: The product is shipped with dry ice (shipment cost to Europe: 160 €). Store at -80°C for the long term. After thawing may be stored for short-term at 4°C (stable at least 2 weeks at this temperature). Avoid repeated freeze/thaw cycles.

Concentration: 1.0 mg/ml.

Purity: >90 % as determined by SDS-PAGE.

Image: SDS-PAGE showing SCoV2-rSκ product 21-S2SIN1-TCg-F at approximately 160 kDa (1, 3 and 5 μg/lane).

Applications (tested): ELISA, other immunoassays, Western blot, SDS-PAGE.

Quality: According to the expressed construct, purified SCoV2-rSκ protein should be trimer in the stabilized prefusion conformation. Full-length trimeric protein enables detection of more antibodies against SCoV2-S, than shorter protein constructs (e.g., RBD or S1). It provides a tool to develop highly sensitive immunoassays. This product 21-S2SIN1-TCg-F showed similar results in ELISA with COVID-19 positive and negative patient sera, as initial sequence SCoV2-rS protein construct (see product 20-S2S-TCg-G information), but a lesser number of individual sera was tested.

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Note: Biotinylated form of this product is available under request.