>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
155 - 175 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.1.1.529 S (GCN4-IZ) His Protein, CF Scientific Data Examples
Recombinant SARS-CoV-2 B.1.1.529 Spike (GCN4-IZ) His-tag Protein Binding Activity.
Recombinant SARS-CoV-2 B.1.1.529 Spike (GCN4-IZ) His-tag (Catalog # 11061-CV) binds Recombinant Human ACE-2 His-tag (933-ZN) in a functional ELISA.
Recombinant SARS-CoV-2 B.1.1.529 Spike (GCN4-IZ) His-tag Protein SDS-PAGE.
2 μg/lane of Recombinant SARS-CoV-2 B.1.1.529 Spike (GCN4-IZ) His-tag Protein (Catalog # 11061-CV) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 155-175 kDa.
Recombinant SARS-CoV-2 B.1.1.529 Spike (GCN4-IZ) His-tag Protein binds to Recombinant Human ACE-2 by surface plasmon resonance
Recombinant SARS-CoV-2 B.1.1.529 Spike (GCN4-IZ) His-tag Protein (Catalog #11061-CV) was immobilized on a Biacore Sensor Chip CM5, and binding to recombinant human ACE-2 (933-ZN) was measured at a concentration range between 0.021 nM and 53.1 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=3.63 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.
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-CoV 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). The S protein of SARS-CoV-2 shares 75% and 29% aa sequence identity with S protein of SARS-CoV-1 and MERS, respectively. The S Protein of the SARS-CoV-2 virus, like the SARS-CoV-1 counterpart, binds a metallopeptidase, Angiotensin-Converting Enzyme 2 (ACE-2), but with much higher affinity and faster binding kinetics through the receptor binding domain (RBD) located in the C-terminal region of S1 subunit (6). It has been demonstrated that the S Protein can invade host cells through the CD147/EMMPRIN receptor and mediate membrane fusion (7, 8). Polyclonal antibodies to the RBD of the SARS-CoV-2 protein have been shown to inhibit interaction with the ACE-2 receptor, confirming RBD as an attractive target for vaccinations or antiviral therapy (9). There is also promising work showing that the RBD may be used to detect presence of neutralizing antibodies present in a patient's bloodstream, consistent with developed immunity after exposure to the SARS-CoV-2 (10). Several emerging SARS-CoV-2 genomes have been identified including the Omicron, or B.1.1.529, variant. First identified in November 2021 in South Africa, the Omicron variant quickly became the predominant SARS-CoV-2 variant and is considered a variant of concern (VOC). The Omicron variant contains 32 mutations in the S protein, 3 to 4 times more than in other SARS-CoV-2 variants, that potentially affect viral fitness and transmissibility (11). Of these mutations,15 are located in the RBD domain and allow the Omicron variant to bind ACE-2 with greater affinity and, potentially, increased transmissibility (11, 12). Several additional mutations throughout the S protein have been shown or are predicted to enhance spike cleavage and could aid transmission (13-15). The study of the Omicron variant's impact on immune escape and reduced neutralization activity to monoclonal antibodies along with an increased risk of reinfection, even among vaccinated individuals, remains ongoing (16).
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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