Recombinant SARS-CoV-2 BA.2.75 Spike RBD His-tag Protein, CF

Recombinant SARS-CoV-2 BA.2.75 Spike RBD His-tag (Catalog # 11259-CV) binds Recombinant Human ACE-2 Fc Chimera (10544-ZN) in a functional ELISA.

2 μg/lane of Recombinant SARS-CoV-2 BA.2.75 Spike RBD His-tag Protein (Catalog # 11259-CV) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 33-39 kDa.

• Applications: Bioactivity
• Format: Carrier-Free

Recombinant SARS-CoV-2 BA.2.75 Spike RBD His-tag Protein, CF Summary

• 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 RBD protein
  Arg319-Phe541 (Gly339His, Ser371Phe, Ser373Pro, Ser375Phe, Thr376Ala, Asp405Asn, Arg408Ser, Lys417Asn, Asn440Lys, Gly446Ser, Asn460Lys, Ser477Asn, Thr478Lys, Glu484Ala, Gln498Arg, Asn501Tyr, Tyr505His), with a C-terminal 6-His tag
• Accession #: YP_009724390.1
• N-terminal Sequence: Arg319
• 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: 26 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: 33-39 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 BA.2.75 Spike RBD His-tag Protein, CF

• Spike RBD

Background

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 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). Based on amino acid (aa) sequence homology, the SARS-CoV-2 RBD has 73% identity with SARS-CoV-1 RBD, but only 22% homology with the MERS RBD. 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). The BA.2.75 subvariant was reported to show significantly higher binding affinity to ACE-2 compared to another dominant subvariant BA.5 (17).

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. Ortega, J.T. et al. (2020) EXCLI J. 19:410.
7. Wang, K. et al. (2020) bioRxiv https://www.biorxiv.org/content/10.1101/2020.03.14.988345v1.
8. Isabel, S. et al. (2020) Sci Rep. 10, 14031. https://doi.org/10.1038/s41598-020-70827-z.
9. Tai, W. et al. (2020) Cell. Mol. Immunol. 17:613.
10. Okba, N. M. A. et al. (2020). Emerg. Infect. Dis. https://doi.org/10.3201/eid2607.200841.
11. Shah, M. and Woo, H.G. (2021) bioRxiv https://doi.org/10.1101/2021.12.04.471200.
12. Lupala, C.S. et al. (2021) bioRxiv https://doi.org/10.1101/2021.12.10.472102.
13. Zhang, L. et al. (2020) Nat Commun. 11:6013.
14. Lasek-Nesselquist, E. et al. (2021) medRxiv https://doi.org/10.1101/2021.03.10.21253285.
15. Scheepers, C. et al. (2021) medRxiv https://doi.org/10.1101/2021.08.20.21262342.
16. Callaway, E. and Ledford, H. (2021) Nature 600:197.
17. Cao, Y. et al. (2022) bioRxiv  https://doi.org/10.1101/2022.07.18.500332.

Publications for Spike RBD (11259-CV)(1)

Publication using 11259-CV

• Puarattana-Aroonkorn, S;Tharakaraman, K;Suriyawipada, D;Ruchirawat, M;Fuangthong, M;Sasisekharan, R;Artpradit, C; Rapid and Scalable Production of Functional SARS-CoV-2 Virus-like Particles (VLPs) by a Stable HEK293 Cell Pool Vaccines 2024-05-21 [PMID: 38932290] (Western Blot Standard, N/A)

Bioinformatics

• Uniprot:
  • YP_009724390.1(Rabbit)