SARS-CoV-2 Spike S1 Subunit Alexa Fluor® 350-conjugated Antibody

R&D Systems, part of Bio-Techne | Catalog # FAB105403U

R&D Systems, part of Bio-Techne

Key Product Details

Species Reactivity

SARS-CoV-2

Applications

Flow Cytometry

Label

Alexa Fluor 350 (Excitation = 346 nm, Emission = 442 nm)

Antibody Source

Monoclonal Mouse IgG1 Clone # 1035206

View all Spike S1 Subunit Antibodies »

Product Specifications

Immunogen

HEK293-derived SARS-CoV-2 Spike S1 Subunit protein
Accession # YP_009724390.1

Specificity

Detects SARS-CoV-2 Spike S1 subunit in direct ELISAs and Western blots. No cross-reactivity with SARS-CoV-2 Spike RBD is observed in direct ELISAs or Western blots.

Clonality

Monoclonal

Host

Mouse

Isotype

IgG1

Applications

Application
Recommended Usage

Flow Cytometry

0.25-1 µg/106 cells
Sample: SARS-CoV-2 Spike protein bound to ACE-2 in live or fixed HEK293 Human Cell Line Transfected with Human ACE-2 and eGFP

Formulation, Preparation, and Storage

Purification

Protein A or G purified from hybridoma culture supernatant

Formulation

Supplied 0.2 mg/mL in a saline solution containing BSA and Sodium Azide.

Shipping

The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.

Stability & Storage

Protect from light. Do not freeze.
  • 12 months from date of receipt, 2 to 8 °C as supplied.

Background: Spike S1 Subunit

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 (ACE2), but with much higher affinity and faster binding kinetics (9). Before binding to the ACE2 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 ACE2 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).

References

  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.

Long Name

Spike Protein, S1 Subunit

Alternate Names

SARS-CoV-2

UniProt

YP_009724390.1

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Product Specific Notices


This product is provided under an agreement between Life Technologies Corporation and R&D Systems, Inc, and the manufacture, use, sale or import of this product is subject to one or more US patents and corresponding non-US equivalents, owned by Life Technologies Corporation and its affiliates. The purchase of this product conveys to the buyer the non-transferable right to use the purchased amount of the product and components of the product only in research conducted by the buyer (whether the buyer is an academic or for-profit entity). The sale of this product is expressly conditioned on the buyer not using the product or its components (1) in manufacturing; (2) to provide a service, information, or data to an unaffiliated third party for payment; (3) for therapeutic, diagnostic or prophylactic purposes; (4) to resell, sell, or otherwise transfer this product or its components to any third party, or for any other commercial purpose. Life Technologies Corporation will not assert a claim against the buyer of the infringement of the above patents based on the manufacture, use or sale of a commercial product developed in research by the buyer in which this product or its components was employed, provided that neither this product nor any of its components was used in the manufacture of such product. For information on purchasing a license to this product for purposes other than research, contact Life Technologies Corporation, Cell Analysis Business Unit, Business Development, 29851 Willow Creek Road, Eugene, OR 97402, Tel: (541) 465-8300. Fax: (541) 335-0354.

For research use only

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