Recombinant SARS-CoV-2 B.1.351 S1 NTD His-tag Protein, CF

Catalog #: 11113-CV Datasheet / COA / SDS

Catalog #	Availability	Size / Price	Qty
11113-CV-100

Recombinant SARS-CoV-2 B.1.351 Spike S1 NTD His-tag Protein SDS-PAGE

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All Spike S1 Subunit Proteins and Enzymes

Product Details

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Summary Product Datasheets Carrier Free Data Images Reconstitution Calculator Background Related Research Areas

Recombinant SARS-CoV-2 B.1.351 S1 NTD His-tag Protein, CF Summary

Product Specifications

Purity

>95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.

Endotoxin Level

<0.10 EU per 1 μg of the protein by the LAL method.

Activity

Bioassay data are not available.

Source

Human embryonic kidney cell, HEK293-derived sars-cov-2 Spike S1 Subunit protein
Val16-Leu303 (Leu18Phe, Asp80Ala, Asp215Gly, Leu242del, Ala243del, Leu244del), with a C-terminal 6-His tag

Accession #

YP_009724390.1

N-terminal Sequence
Analysis

Val16

Predicted Molecular Mass

33 kDa

SDS-PAGE

55-61 kDa, under reducing conditions.

Product Datasheets

11113-CV

Product Datasheet

COA

SDS

Carrier Free

What does CF mean?

CF stands for Carrier Free (CF). We typically add Bovine Serum Albumin (BSA) as a carrier protein to our recombinant proteins. Adding a carrier protein enhances protein stability, increases shelf-life, and allows the recombinant protein to be stored at a more dilute concentration. The carrier free version does not contain BSA.

What formulation is right for me?

In general, we advise purchasing the recombinant protein with BSA for use in cell or tissue culture, or as an ELISA standard. In contrast, the carrier free protein is recommended for applications, in which the presence of BSA could interfere.

11113-CV

Formulation	Lyophilized from a 0.2 μm filtered solution in PBS with Trehalose.
Reconstitution	Reconstitute at 500 μg/mL in PBS.
Shipping	The product is shipped at ambient temperature. Upon receipt, store it immediately at the temperature recommended below.
Stability & 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.

Scientific Data

SDS-PAGE

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2 μg/lane of Recombinant SARS-CoV-2 B.1.351 Spike S1 NTD His-tag Protein (Catalog # 11113-CV) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at 55-61 kDa.

Reconstitution Calculator

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 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 S1 subunit can be further divided into an N-terminal domain (NTD) and a receptor binding domain (RBD). The SARS-CoV-2 NTD shares 50% and 20% amino acid (aa) sequence identity with the NTD of SARS-CoV-1 and MERS-CoV, respectively. The NTD is reported to bind L-SIGN and DC-SIGN in cells that don't express the ACE-2 receptor (6). Despite being heavily glycosylated, the NTD is capable of eliciting an immune response to produce potent neutralization antibodies, although at a reduced level than the ones targeting the RBD. Three immunogenic regions have been identified in the NTD: aa 14-20, aa 140-158, and aa 245-264 (7). Antibody cocktails targeting both NTD and RBD could provide better protection against SARS-CoV-2 infection. There are six mutations in the NTD of the B.1.351 variant.

References

Wu, F. et al. (2020) Nature 579:265.
Tortorici, M.A. and D. Veesler (2019). Adv. Virus Res. 105:93.
Bosch, B.J. et al. (2003) J. Virol. 77:8801.
Belouzard, S. et al. (2009) Proc. Natl. Acad. Sci. 106:5871.
Millet, J.K. and G.R. Whittaker (2015) Virus Res. 202:120.
Soh, W.T. et al. (2020) bioRxiv doi: https://doi.org/10.1101/2020.11.05.369264.
Matthew, M. et al. (2021) Cell 184:2332.