Human embryonic kidney cell, HEK293-derived sars-cov-2 Spike RBD protein Arg319-Phe541 (Arg346Lys, Lys417Asn, Glu484Lys, Asn501Tyr), with a C-terminal 6-His tag
>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
<0.10 EU per 1 μg of the protein by the LAL method.
N-terminal sequence Analysis
Predicted Molecular Mass
32-38 kDa, under reducing conditions.
Measured by its binding ability in a functional ELISA with Recombinant Human ACE-2 His-tag (Catalog # 933-ZN).
Recombinant SARS-CoV-2 B.1.621/K417N RBD His-tag Protein, CF Scientific Data Examples
Recombinant SARS-CoV-2 B.1.621 K417N RBD His-tag Protein Binding Activity.
Recombinant SARS-CoV-2 B.1.621 K417N Spike RBD His-tag (Catalog # 10981-CV) binds Recombinant Human ACE-2 His-tag (933-ZN) in a functional ELISA.
Recombinant SARS-CoV-2 B.1.621 K417N RBD His-tag Protein SDS-PAGE.
2 μg/lane of Recombinant SARS-CoV-2 B.1.621 K417N Spike RBD Histag (Catalog # 10981-CV) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 32-38 kDa.
Formulation, Preparation and Storage
What does CF mean?
CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our
Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant
protein to be stored at a more dilute concentration.
The carrier free version does not contain BSA.
What formulation is right for me?
In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or
as an ELISA standard.
In contrast, the carrier free protein is recommended for applications, in which the presence of BSA
Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose.
Reconstitute at 500 μg/mL in PBS.
The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage:
Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
12 months from date of receipt, -20 to -70 °C as supplied.
1 month, 2 to 8 °C under sterile conditions after reconstitution.
3 months, -20 to -70 °C under sterile conditions after reconstitution.
Background: Spike RBD
SARS-CoV-2, which causes the global pandemic coronavirus disease 2019 (Covid-19), belongs to a family of viruses known as coronaviruses that also include MERS and SARS-CoV-1. Coronaviruses are commonly comprised of four structural proteins: Spike protein (S), Envelope protein (E), Membrane protein (M) and Nucleocapsid protein (N) (1). The SARS-CoV-2 S protein is a glycoprotein that mediates membrane fusion and viral entry. The S protein is homotrimeric, with each ~180-kDa monomer consisting of two subunits, S1 and S2 (2). In SARS-CoV-2, as with most coronaviruses, proteolytic cleavage of the S protein into S1 and S2 subunits is required for activation. The S1 subunit is focused on attachment of the protein to the host receptor while the S2 subunit is involved with cell fusion (3-5). A metallopeptidase, angiotensin-converting enzyme 2 (ACE2), has been identified as a functional receptor for SARS-CoV-2 through interaction with a receptor binding domain (RBD) located at the C-terminus of S1 subunit (6,7). The RBD of SARS-CoV-2 shares 73% amino acid (aa) identity with the RBD of the SARS-CoV-1, but only 22% aa identity with the RBD of MERS. A SARS-CoV-2 variant (B.1.621; also known as mu variant) carrying the aa substitution Arg346Lys, Glu484Lys, and Asn501Tyr in RBD protein was originally identified in samples from Colombia and spreaded rapidly to US and Europe (8). An additional mutation Lys417Asn was also identified in some B.1.621 variants. Whether these mutations in the spike protein would cause more severe symptom or decrease the efficacy of vaccine-induced immunity is still under investigation.
Wu, F. et al. (2020) Nature 579:265.
Tortorici, M.A. and D. Veesler (2019) Adv. Virus Res. 105:93.
Bosch, B.J. et al. (2003) J. Virol. 77:8801.
Belouzard, S. et al. (2009) Proc. Natl. Acad. Sci. 106:5871.
Millet, J.K. and G.R. Whittaker (2015) Virus Res. 202:120.
Which Brands are Currently Available on bio‑techne.com? R&D Systems, Tocris Bioscience and ProteinSimple branded products are available to purchase through bio‑techne.com. ProteinSimple branded instruments are available to quote. ACD branded products will be available on bio‑techne.com in the near future. Novus Biologicals branded products are not currently available on bio‑techne.com and can be found at novusbio.com.
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