Original strain - Fc-tagged RBD Protein

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SARS-CoV-2 Spike RBD-Fc fusion protein

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50 µg


SARS-CoV-2 Spike RBD with C-terminal Fc tag

Protein description

Potential applications of soluble spike proteins
Potential applications of soluble spike proteins

The SARS-CoV-2 (2019-nCoV) Spike RBD (receptor binding domain) has been identified as the key viral element allowing the virus docking to the target cells. RDB is recognized by the ACE2 surface membrane receptor [1-3]. RBD is a candidate for subunit prophylactic vaccines against SARS-CoVs [4, 5]. RBD is also at the center of therapeutic approaches, such as the development and testing of small peptide inhibitors or soluble ACE2 to block the SARS-CoV-2 entry into target cells [6].
Spike-RBD-Fc was generated by fusing the C-terminus of SARS-CoV-2 Spike RBD [R319-F541] to a human IgG1 Fc region.
The SARS-CoV-2 viral sequence used is from the Wuhan-Hu-1 (D614) isolate.
This protein has been produced in CHO cells and purified by affinity chromatography (See Details and Specifications for more information).


  • Vaccination studies: using combinations of Spike protein antigens and adjuvants
  • Antibody screening: finding anti-Spike antibodies that can neutralize the SARS-CoV-2 infection
  • Inhibitor screening: finding small molecules, or antibodies able to block the SARS-CoV-2 RBD interaction with the ACE2 receptor
  • ACE2 cellular expression screening: in primary isolated cells or transfected cells

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Learn more on SARS-CoV-2Learn more about SARS-CoV-2 infection cycle, immune responses, and potential therapeutics.



1. Li F., 2016. Structure, function, and evolution of coronavirus spike proteins. Annu. Rev. Virol. 3:237-261.
2. Li F. et al., 2005. Structure of SARS coronavirus spike receptor-binding domain complexed with receptor. Science. 309:1864-1868.
3. Walls A.C. et al., 2020. Structure, function, and antigenicity of the SARS-CoV-2 spike glycoprotein. Cell. 181(2):281-292.e6.
4. Wang N. et al., 2020. Subunit vaccines against emerging pathogenic human coronaviruses. Front. Microbiol. 11:298. DOI: 10.3389/fmicb.2020.00298.
5. Padron-Regalado E., 2020. Vaccines for SARS-CoV-2: Lessons from other coronavirus strains. Infect. Dis. Ther. DOI: 10.1007/s40121-020-00300-x.
6. Monteil al., 2020. Inhibition of SARS-CoV-2 infections in engineered human tissues using clinical-grade soluble human ACE2. Cell. 181:1-9.


Spike-RBD-Fc analysis by SDS PAGE
Spike-RBD-Fc analysis by SDS PAGE

SDS PAGE analysis of the Spike-RBD-Fc protein.1 μg of the fusion protein was loaded on a 12% Mini-PROTEAN® TGX Stain-Free™ Precast Gels (Bio-Rad). Detection was performed as per manufacturer’s intructions.

Recognition of Spike-RBD-Fc by anAnti-SARS-CoV-Spike human IgM
Recognition of Spike-RBD-Fc by anAnti-SARS-CoV-Spike human IgM

ELISA detection of the SARS-CoV-2 Spike-RBD-Fc fusion protein with the Anti-SARS-CoV-Spike human IgM. Anti-SARS-CoV-Spike hIgM antibody (5 μg/ml) was coated on ELISA plates overnight. A 3-fold serial dilution of Spike-RBD-Fc (red  curve) or of CTLA4-hFc control protein (grey curve) was realized for the capture step. An HRP-labelled anti-hFc antibody (1/1000 dilution) and the HRP substrate OPD (o-phenylenediamine dihydrochloride) were used for the detection step. Absorbance was read at 490 nm.

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  • Protein construction: RBD [R319-F541] from the Spike glycoprotein with a C-terminal human IgG1 Fc tag 
  • Accession sequence: YP_009724390
  • Species: SARS-CoV-2 (2019-nCoV); Wuhan-Hu-1 (D614) isolate
  • Tag: C-terminal human IgG1 Fc
  • Total protein size: 473 a.a. (secreted form)
  • Molecular weight: ~59 kDa (SDS-PAGE)
  • Purification: Protein A affinity chromatography
  • Purity: >95% (SDS-PAGE)
  • Quality control:
    - The protein has been validated by ELISA upon incubation with a coated Anti-SARS-CoV-Spike-RBD hIgM mAb (clone CR3022)
    - The absence of bacterial contamination (e.g. lipoproteins and endotoxins) has been confirmed using HEK-Blue™ TLR2 and HEK-Blue™ TLR4 cellular assays.
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  • 50 μg of lyophilized protein
  • 1.5 ml of endotoxin-free water

room temperature The product is shipped at room temperature.

store Lyophilized protein should be stored at -20 ̊C.

stability Resuspended protein is stable up to 1 month when stored at 4°C, and 1 year when stored at -20°C

Avoid repeated freeze-thaw cycles.

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Learn more about the SARS-CoV-2 Spike protein.

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