COVID-19 Proteins

Recombinant SARS-CoV-2 Proteins

The nucleocapsid protein (N-protein) and spike protein (S-protein) are encoded by all coronaviruses, including the coronavirus (SARS-CoV-2, COVID-19) that was first detected in Wuhan City, China, in December 2019. Both recombinant forms of these proteins are now available from RayBiotech to advance infectious disease research (Figures 1 & 2).

Nucleocapsid Protein (N-Protein)

The nucleocapsid protein (N-protein) is a structural protein that binds to the coronavirus RNA genome, thus creating a shell (or capsid) around the enclosed nucleic acid. The N-protein also 1) interacts with the viral membrane protein during viral assembly, 2) assists in RNA synthesis and folding, 3) plays a role in virus budding, and 4) affects host cell responses, including cell cycle and translation.

Nucleocapsid Protein (N-Protein)
Figure 1. N-protein domains 
RBD = RNA binding domain; IDR = intrinsically disordered region; SR = serine-arginine-rich; NLS = nuclear localization signal.

Spike Protein (S-Protein)

The spike protein (S-protein) performs two primary tasks that aid in host infection: 1) mediates the attachment between the virus and host cell surface receptors, and 2) facilitates viral entry into the host cell by assisting in the fusion of the viral and host cell membranes.

Spike Protein (S-Protein)
Figure 2. S-protein domains  
RBD = receptor binding domain; SP = signal peptide; SR = serine-arginine-rich; TM = transmembrane domain


ACE2 is an endogenous membrane protein that enables COVID-19 infection. During infection, the extracellular peptidase domain of ACE2 binds to the receptor binding domain of spike protein, which is a surface protein on SARS-CoV-2.

ACE2 Protein
Figure 3. Human ACE2 domains  
SP = Signal peptide; TM = transmembrane domain; ID = Intracellular domain


Protein Catalog # Protein Domain Purification Expression Host Expression Region Tag MW (kDa)
N protein, Nucleocapsid 230-30164 Full length Purified HEK293 Cell Met1 - Ala419 C-terminal His-tag ⁓50 kDa
230-01104 Purified E.coli Met1 - Ala419 N-terminal His-tag ⁓50 kDa
230-20409 Unpurified HEK293 Cell Met1 - Ala419 C-terminal His-tag ⁓50 kDa
S Protein, Spike 230-01102 S1 subunit, RBD Purified E.coli Arg319 - Phe541 N-terminal His-tag ⁓25 kDa
230-30162 Purified HEK293 Cell Arg319 - Phe541 C-terminal His-tag ⁓25 kDa
230-20406 Unpurified HEK293 Cell Arg319 - Phe541 C-terminal His-tag ⁓25 kDa
230-20405 Unpurified HEK293 Cell Arg319 - Phe541 C-terminal Fc-tag ⁓50 kDa
230-01101 S1 subunit, full-length Purified E.coli Val16 - Gln690 N-terminal His-tag ⁓75 kDa
230-20407 Unpurified HEK293 Cell Val16 - Gln690 C-terminal His-tag ⁓75 kDa
230-01103 S2 subunit, full-length Purified E.coli Met697 - Pro1213 N-terminal His-tag ⁓58 kDa
230-20408 Unpurified HEK293 Cell Met697 - Pro1213 C-terminal His-tag ⁓60 kDa
Human ACE2 230-30165 Full-length Purified HEK293 Cell Gln18-Ser740 C-terminal His-tag ⁓90 kDa

For help identifying the right protein for your research, please contact our technical support team at [email protected] or (888) 494-8555.

Analysis Images

COVID-19 Proteins SDS-PAGE
Figure 4. SDS-PAGE analysis of the purified recombinant SARS-CoV-2 target proteins.
Figure 5. SDS-PAGE analysis of the purified recombinant SARS-CoV-2 target proteins and human ACE2. Lane 1: Protein standard ladder (kDa); Lane 2: Untreated protein under reducing conditions; Lane 3: Treated protein with deglycosylation enzymes under native conditions; Lane 4: Treated protein with deglycosylation enzymes under reducing conditions.
COVID-19 Proteins Western Blot
Figure 6. Western blotting analysis of transfected HEK293 cells shown the secretion and overexpression of SARS-CoV-2 target proteins. The enlarged molecular weight might be due to the abundant post-translation modifications.


  1. F Wu, et al. A new coronavirus associated with human respiratory disease in China. Nature. 579, 265–269 (2020).
  2. N Dong, et al. Genomic and protein structure modelling analysis depicts the origin and infectivity of 2019-nCoV, a new coronavirus which caused a pneumonia outbreak in Wuhan, China. bioRxiv (2020).
  3. M Hoffmann, et al. SARS-CoV-2 Cell Entry Depends on ACE2 and TMPRSS2 and Is Blocked by a Clinically Proven Protease Inhibitor. Cell. 181, 1–10 (2020).
  4. W Li et al. Angiotensin-converting enzyme 2 is a functional receptor for the SARS coronavirus. Nature. 426, 450–454 (2003).