Human embryonic kidney cell, HEK293-derived sars-cov-2 Spike RBD protein Arg319-Phe541 (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
34-38 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.1.351 Spike RBD His Protein, CF Scientific Data Examples
Recombinant SARS-CoV-2 B.1.351 Spike RBD His-tag Protein Bioactivity.
Recombinant SARS-CoV-2 B.1.351 Spike RBD His-tag (Catalog # 10735-CV) binds Recombinant Human ACE-2 His-tag (933-ZN) in a functional ELISA.
Recombinant SARS-CoV-2 B.1.351 Spike RBD His-tag Protein SDS-PAGE.
2 μg/lane of Recombinant SARS-CoV-2 B.1.351 Spike RBD His-tag (Catalog # 10735-CV) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 34-38 kDa.
Binding of ACE-2 to South African variant Spike RBD protein by surface plasmon resonance (SPR).
Recombinant SARS-CoV-2 Spike RBD South African variant B.1.351 was immobilized on a Biacore Sensor Chip CM5, and binding to recombinant human ACE-2 (933-ZN) was measured at a concentration range between 0.18 nM and 47.2 nM. The double-referenced sensorgram was fit to a 1:1 binding model to determine the binding kinetics and affinity, with an affinity constant of KD=2.227 nM. (Biacore T200).
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 carrying amino acid substitutions N501Y, K417N, and E484K in the RBD raised the most concerns. This B.1.351 lineage, also known and 501Y.V2 variant, was first identified in the Eastern Cape province of South Africa in December 2020 and spread quickly to become the most dominant strain in the second COVID wave in South Africa (8). Two of these mutations K417N and E484K locate at the receptor binding motif (RBM) and are not found in other variants (8). The N501Y mutation is also found in London (B.1.1.7 lineage) and Brazil (P.1 lineage). The B.1.351 lineage is reported to enter cells more easily due to its enhanced affinity to ACE-2 receptor (9). It is reported to reduce the efficacy of neutralizing antibody (9, 10).
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.
Setting the standard in quality research reagents for over 30 years
A trusted leader in quality life science reagents
Your trusted supplier for innovative and high performance life science reagents
Proprietary systems and consumables for simpler, more quantitative and affordable protein analysis
Proprietary RNAscope® technology capable of detecting and quantifying RNA biomarkers in situ at single molecule sensitivity
A world leader in developing liquid biopsy based diagnostics