Recombinant SARS-CoV-2 B.1.351 Spike RBD His Protein, CF

Recombinant SARS-CoV-2 B.1.351 Spike RBD His-tag (Catalog # 10735-CV) binds Recombinant Human ACE-2 His-tag (933-ZN) in a functional ELISA.

2 μg/lane of Recombinant SARS-CoV-2 B.1.351 Spike RBD His-tag (Catalog # 10735-CV) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 34-38 kDa.

Recombinant SARS-CoV-2 Spike RBD South African variant B.1.351 was immobilized on a Biacore Sensor Chip CM5, and binding to recombinant human ACE-2 (933-ZN) was measured at a concentration range between 0.18 nM and 47.2 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=2.227 nM.

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

Recombinant SARS-CoV-2 B.1.351 Spike RBD His Protein, CF Summary

• Additional Information: Beta Variant (South Africa), K417N, E484K, N501Y
• Details of Functionality: Measured by its binding ability in a functional ELISA with Recombinant Human ACE-2 His-tag (Catalog # 933-ZN).
• Source: Human embryonic kidney cell, HEK293-derived sars-cov-2 Spike RBD protein
  Arg319-Phe541 (Lys417Asn, Glu484Lys, Asn501Tyr), with a C-terminal 6-His tag
• Accession #: YP_009724390.1
• N-terminal Sequence: Arg 319
• 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: 34-38 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 B.1.351 Spike RBD His 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 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). A metallopeptidase, angiotensin-converting enzyme 2 (ACE2), has been identified as a functional receptor for SARS-CoV-2 through interaction with a receptor binding domain (RBD) located at the C-terminus of S1 subunit (6, 7). The RBD of SARS-CoV-2 shares 73% amino acid (aa) identity with the RBD of the SARS-CoV-1, but only 22% aa identity with the RBD of MERS. A SARS-CoV-2 variant carrying amino acid substitutions N501Y, K417N, and E484K in the RBD raised the most concerns. This B.1.351 lineage, also known and 501Y.V2 variant, was first identified in the Eastern Cape province of South Africa in December 2020 and spread quickly to become the most dominant strain in the second COVID wave in South Africa (8). Two of these mutations K417N and E484K locate at the receptor binding motif (RBM) and are not found in other variants (8). The N501Y mutation is also found in London (B.1.1.7 lineage) and Brazil (P.1 lineage). The B.1.351 lineage is reported to enter cells more easily due to its enhanced affinity to ACE-2 receptor (9). It is reported to reduce the efficacy of neutralizing antibody (9, 10).

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. Li, W. et al. (2003) Nature 426:450.
7. Wong, S.K. et al. (2004) J. Biol. Chem. 279:3197.
8. Tegally, H. et al. (2020) BioRxiv. doi: https://doi.org/10.1101/2020.12.21.20248640.
9. Nelson, G. et al. (2021) BioRxiv. doi: 10.1101/2021.01.13.426558.
10. Wibmer, C.K. et al. (2021) BioRxiv. doi: 10.1101/2021.01.18.427166.

Publications for Spike RBD (10735-CV)(1)

Publication using 10735-CV

• Harless, WW;Lewis, B;Qorri, B;Abdulkhalek, S;Szewczuk, MR; Novel Therapeutic Target Critical for SARS-CoV-2 Infectivity and Induction of the Cytokine Release Syndrome Cells 2023-05-07 [PMID: 37174732] (Bioassay, N/A)

Bioinformatics

• Uniprot:
  • YP_009724390.1(Llama)