Recombinant SARS-CoV Spike S1 Subunit His-tag Protein, CF

Recombinant SARS-CoV Spike S1 Subunit His-tag (Catalog # 10570-CV) binds Recombinant Human ACE-2 His-tag (933-ZN) in a functional ELISA.

2 μg/lane of Recombinant SARS-CoV Spike S1 Subunit His-tag Protein (Catalog # 10570-CV) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 85-98 kDa and 75-85 kDa, respectively.

In a functional flow cytometry test, (A) Recombinant SARS-CoV Spike S1 Subunit His-tag Protein (Catalog # 10570-CV) 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 anti-His Monoclonal Antibody (IC050A), which does not stain the cells in the absence of recombinant protein (B).

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

Recombinant SARS-CoV Spike S1 Subunit His-tag Protein, CF Summary

• Additional Information: Sf21 Insect Cell Expressed
• Details of Functionality: Measured by its binding ability in a functional ELISA with Recombinant Human ACE-2 His-tag (Catalog # 933-ZN).
• Source: Spodoptera frugiperda, Sf 21 (baculovirus)-derived sars-cov Spike S1 Subunit protein
  Ser14-Leu666, with a C-terminal 6-His tag
• Accession #: NP_828851.1
• N-terminal Sequence:

  Ser14

• 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: 74 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: 85-98 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 Spike S1 Subunit His-tag Protein, CF

• SARS-CoV-2
• Spike S1 Subunit

Background

SARS-CoV was discovered in association with cases of severe acute respiratory syndrome (SARS) that infected more than 8,000 persons with over 900 fatalities worldwide in 2002-2003 (1). It belongs to a family of viruses known as coronaviruses that also include MERS and SARS-Cov2 that causes the global pandemic coronavirus disease 2019 (Covid-19). Coronavirus is commonly comprised of four structural proteins: Spike protein(S), Envelope protein (E), Membrane protein (M), and Nucleocapsid protein (N) (1). SARS-CoV S Protein is a type-I trimerized membrane glycoprotein that mediates membrane fusion and viral entry. 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 (2-4). A metallopeptidase, angiotensin-converting enzyme 2 (ACE-2), has been identified as a functional receptor for SARS-CoV through interaction with a receptor binding domain (RBD) located at the C-terminus of S1 subunit (5, 6). Based on amino acid (aa) sequence homology, the S1 subunit of SARS-Cov shares 65% and 24% homology with S1 subunit of SARS-CoV2 and MERS, respectively. 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 (7). Antibodies to S protein especially the S1 subunit of SARS-CoV have been shown to inhibit interaction with the ACE-2 receptor, confirming S1 subunit as an attractive target for vaccinations or antiviral therapy (8).

1. Rota, P.A. et al. (2003) Science 300:1394.
2. Bosch, B.J. et al. (2003). J. Virol. 77:8801.
3. Belouzard, S. et al. (2009) Proc. Natl. Acad. Sci. USA 106:5871.
4. Millet, J.K. and G. R. Whittaker (2015) Virus Res. 202:120.
5. Li, W. et al. (2003) Nature 426:450.
6. Wong, S.K. et al. (2004) J. Biol. Chem. 279:3197.
7. Ortega, J.T. et al. (2020) EXCLI J. 19:410.
8. Du, L. el al. (2009) Nat. Rev. Microbiol. 7:226.

Bioinformatics

• Uniprot:
  • NP_828851.1()