Recombinant SARS-CoV-2 (COVID-19) S1 protein NTD (N234Q), His Tag, 1mg

Background
It's been reported that SARS-CoV-2 can infect the human respiratory epithelial cells through interaction with the human ACE2 receptor. The spike protein is a large type I transmembrane protein containing two subunits, S1 and S2. S1 mainly contains a receptor binding domain (RBD), which is responsible for recognizing the cell surface receptor. S2 contains basic elements needed for the membrane fusion.The S protein plays key parts in the induction of neutralizing-antibody and T-cell responses, as well as protective immunity.

Source
Recombinant SARS-CoV-2 S1 protein NTD (N234Q), His Tag (S1D-C52H7) is expressed from human 293 cells (HEK293). It contains AA Ser 13 - Leu 303(N234Q） (Accession # QHD43416.1(N234Q)). Predicted N-terminus: Ser 13

Molecular Characterization
This protein carries a polyhistidine tag at the C-terminus.The protein has a calculated MW of 34.9 kDa. The protein migrates as 45-65 kDa under reducing (R) condition (SDS-PAGE) due to Glycosylation.

Endotoxin
Less than 1.0 EU per μg by the LAL method.

Purity
>90% as determined by SDS-PAGE.

Formulation
Lyophilized from 0.22 μm filtered solution in PBS, pH7.4. Normally Trehalose are added as protectants before lyophilization.

Reconstitution
See Certificate of Analysis for reconstitution instructions and specific concentrations.

Bioactivity
Please refer to product data sheet.

Storage
Avoid repeated freeze-thaw cycles.
This product is stable after storage at:
-20°C to -70°C for 12 months in lyophilized state;
-70^°C for 3 months under sterile conditions after reconstitution.

References

(1) Wan Y, et al. J Virol. 2020. pii: JVI.00127-20.
(2) Benvenuto D, et al. J Med Virol. 2020.
(3) Chang CY, et al. AMB Express. 2020. 10(1):20.