High quality reagents for innate immunity research, vaccine development and drug discovery

		Recombinant SARS-CoV2 Spike protein Receptor Binding Domain (RBD)
		Background The SARS-CoV-2 virus, which is responsible for the respiratory illness referred to as COVID-19, infects human cells by means of interaction between the viral spike (S) protein and the angiotensin-converting enzyme 2 (ACE2) receptor on the surface of target cells. The receptor-binding domain (RBD) is the specific region of the spike protein that is responsible for this interaction, enabling virus attachment and entry [1]. Being prominently exposed on the surface of the viral particle, the RBD is also a dominant antigen of the humoral immune response to SARS-CoV-2 infection. For these reasons, it has become the most commonly targeted antigen for the generation of candidate and approved vaccines, and for use in studies of serological conversion following vaccination or natural infection [2,3]. Caithness Biotech RBD protein comprises amino acids Arg 319 to Phe 541 of the spike protein of the original SARS-CoV-2 viral sequence, first reported in January 2020 (Wuhan-Hu-1, Pango lineage A, Nextstrain Clade 19A [1]). Potential applications of RBD protein include use in vaccine development, serological assays (such as ELISAs to measure RBD-specific antibody responses), drug discovery for inhibition of ACE2 binding and use in bioassays to explore other potential biological activities.
		Description
		Product	Recombinant SARS-CoV2 Spike protein Receptor Binding Domain (RBD)
		Size / volume	100 μg
		Expression system	HEK-293 cells
		Amino acids	Arg 319 to Phe 541, NCBI reference sequence YP_009724390.1
		Tags	C-terminal 6x His tag
		Sequence graphic
		Intended use	For laboratory research only, not for clinical or diagnostic use.
		Specifications
		Format	Lyophilised from sterile PBS (pH 7.4) with trehalose as protectant and without additional carrier protein.
		Purity	>95% by SDS PAGE
		Molecular weight	Migrates at ~ 38 kDa (glycosylation present)
		LPS content	< 0.1 ng / μg (by HEK-293-TLR4 bioassay, relative to E. coli LPS standard)
		BLP content	< 0.1 ng / μg (by HEK-293-TLR2 bioassay, relative to Pam3CSK4 standard)
		Amino acid sequence	See Technical data sheet.
		Applications	ELISA / bioassay / SDS PAGE / binding studies / immunoassays
		Pricing
		Catalogue number	RBD-01
		Price per unit	£150 per vial of 100 μg
		Figure 1: SDS PAGE analysis 1 μg of recombinant protein was separated by reducing SDS PAGE and visualised by Coomassie Blue staining. Caithness Biotech recombinant SARS-CoV2 RBD migrates at approximately 38 kDa due to glycosylation.		Figure 2: Validation of RBD mAb binding by ELISA RBD protein was plated at 0.1 μg per well of a high binding 96-well plate and allowed to bind overnight. The binding of a SARS-Cov2 RBD specific monoclonal antibody at indicated concentrations was then measured by ELISA. Binding of the mAb to BSA only is shown as a negative control.		Figure 3: Validation of low levels of TLR2 stimulating contaminants HEK-293 cells were transfected with NF-κB reporter and CD14 together with TLR2, then treated with indicated concentrations of Pam3CSK4, or 1 μg/ml of reconstituted RBD protein. NF-κB signalling was measured after overnight treatment by luminometry.
		Product flyer Please click here to download the product flyer.		Technical data sheet Please click here to download the product technical data sheet.
	References
	[1] Zhou P, et al. A pneumonia outbreak associated with a new coronavirus of probable bat origin. Nature 579:270-273 (2020) [2] Kleanthous H, Silverman JM, Makar KW, Yoon I-K, Jackson N, Vaughn DW. Scientific rationale for developing potent RBD-based vaccines targeting COVID-19. npj Vaccines 6:128 (2021) [3] Amanat F, et al. A serological assay to detect SARS-CoV-2 seroconversion in humans. Nature Medicine 26:1033-1036 (2020)

 

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Caithness Biotechnologies Ltd., 72 Boston Road, Leicester, UK, LE4 1HB. Telephone: +44 (0) 116 326 3802 | email: contact@caithnessbiotechnologies.com