Recombinant SARS-CoV-2 Spike S1 Subunit Biotin Protein, CF

Biotinylated Recombinant SARS-CoV-2 Spike S1 Subunit His-tag (Catalog # BT10569) binds Recombinant Human ACE-2 Fc Chimera (10544-ZN) in a functional ELISA.

2 μg/lane of Biotinylated Recombinant SARS-CoV-2 Spike S1 Subunit Biotin Protein, CF (Catalog # BT10569) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 105-140 kDa.

In a functional flow cytometry test, (A) Recombinant SARS-CoV-2 Spike S1 Biotin Protein (Catalog # BT10569) binds to HEK293 human embryonic kidney cell line transfected with recombinant human ACE-2 and EGFP. Ligand binding was detected by staining cells with APC-conjugated Streptavidin (F0050), which does not stain the cells in the absence of recombinant protein (B).

• Reactivity: V
• Applications: Bioactivity
• Format: Carrier-Free

Recombinant SARS-CoV-2 Spike S1 Subunit Biotin Protein, CF Summary

• Additional Information: His-tag. Biotinylated via Amines
• Details of Functionality:

  Measured by its binding ability in a functional ELISA with Recombinant Human ACE-2 Fc Chimera (Catalog # 10544-ZN).

• Source: Human embryonic kidney cell, HEK293-derived sars-cov-2 Spike S1 Subunit protein
  Val16-Pro681, with a C-terminal 6-His tag
• Accession #: YP_009724390.1
• N-terminal Sequence: Val16
• Structure / Form: Biotinylated via amines
• Protein/Peptide Type: Recombinant Proteins
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Endotoxin Note: <0.10 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Bioactivity
• Theoretical MW: 75 kDa.
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 105-140 kDa, under reducing conditions

Packaging, Storage & Formulations

• 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.
• Buffer: Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose.
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Reconstitution Instructions: Reconstitute at 500 μg/mL in PBS.

Notes

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Alternate Names for Recombinant SARS-CoV-2 Spike S1 Subunit Biotin Protein, CF

• SARS-CoV-2
• Spike S1 Subunit

Background

SARS-CoV-2, which causes the global pandemic coronavirus disease 2019 (Covid-19), belongs to a family of viruses known as coronaviruses that are commonly comprised of four structural proteins: Spike protein(S), Envelope protein (E), Membrane protein (M), and Nucleocapsid protein (N) (1). SARS-CoV-2 Spike Protein (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 two distinct peptides, 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). Based on structural biology studies, the receptor binding domain (RBD), located in the C-terminal region of S1, can be oriented either in the up/standing or down/lying state (6). The standing state is associated with higher pathogenicity and both SARS-CoV-1 and MERS can access this state due to the flexibility in their respective RBDs. A similar two-state structure and flexibility is found in the SARS-CoV-2 RBD (7). Based on amino acid (aa) sequence homology, the SARS-CoV-2 S1 subunit has 65% identity with SARS-CoV-1 S1 subunit, but only 22% homology with the MERS S1 subunit. The low aa sequence homology is consistent with the finding that SARS and MERS bind different cellular receptors (8). The S Protein of the SARS-CoV-2 virus, like the SARS-CoV-1 counterpart, binds Angiotensin-Converting Enzyme 2 (ACE-2), but with much higher affinity and faster binding kinetics (9). Before binding to the ACE-2 receptor, structural analysis of the S1 trimer shows that only one of the three RBD domains in the trimeric structure is in the "up" conformation. This is an unstable and transient state that passes between trimeric subunits but is nevertheless an exposed state to be targeted for neutralizing antibody therapy (10). Polyclonal antibodies to the RBD of the SARS-CoV-2 S1 subunit have been shown to inhibit interaction with the ACE-2 receptor, confirming RBD as an attractive target for vaccinations or antiviral therapy (11). 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 virus (12). Lastly, it has been demonstrated the S Protein can invade host cells through the CD147/EMMPRIN receptor and mediate membrane fusion (13, 14).

1. Wu, F. et al. (2020) Nature 579:265.
2. Tortorici, M.A. and D. Veesler (2019). Adv. Virus Res. 105:93.
3. Bosch, B.J. et al. (2003). J. Virol. 77:8801.
4. Belouzard, S. et al. (2009) Proc. Natl. Acad. Sci. 106:5871.
5. Millet, J.K. and G. R. Whittaker (2015) Virus Res. 202:120.
6. Yuan, Y. et al. (2017) Nat. Commun. 8:15092.
7. Walls, A.C. et al. (2010) Cell 180:281.
8. Jiang, S. et al. (2020) Trends. Immunol. https://doi.org/10.1016/j.it.2020.03.007.
9. Ortega, J.T. et al. (2020) EXCLI J. 19:410.
10. Wrapp, D. et al. (2020) Science 367:1260.
11. Tai, W. et al. (2020) Cell. Mol. Immunol. https://doi.org/10.1016/j.it.2020.03.007.
12. Okba, N. M. A. et al. (2020). Emerg. Infect. Dis. https://doi.org/10.3201/eid2607.200841.
13. Wang, X. et al. (2020) https://doi.org/10.1038/s41423-020-0424-9.
14. Wang, K. et al. (2020) bioRxiv https://www.biorxiv.org/content/10.1101/2020.03.14.988345v1.

Publications for SARS-CoV-2 Spike S1 Protein (BT10569)(2)

Publications using BT10569

• ES Kim, MT Jeon, KS Kim, S Lee, S Kim, DG Kim Spike Proteins of SARS-CoV-2 Induce Pathological Changes in Molecular Delivery and Metabolic Function in the Brain Endothelial Cells Viruses, 2021-10-08;13(10):. 2021-10-08 [PMID: 34696455] (Bioassay, Human, Mouse)
• W Ouyang, T Xie, H Fang, C Gao, T Stantchev, KA Clouse, K Yuan, T Ju, DM Frucht Variable Induction of Pro-Inflammatory Cytokines by Commercial SARS CoV-2 Spike Protein Reagents: Potential Impacts of LPS on In Vitro Modeling and Pathogenic Mechanisms In Vivo International Journal of Molecular Sciences, 2021-07-14;22(14):. 2021-07-14 [PMID: 34299155] (Bioassay, Human)

Bioinformatics

• Uniprot:
  • YP_009724390.1(Llama)