The SARS-CoV-2 virus in COVID-19 is composed of two main proteins, the nucleocapsid protein (N-protein) and spike protein (S-protein). These proteins are encoded by all coronaviruses. Both recombinant forms of these specific COVID-19 proteins are now available from RayBiotech to advance infectious disease research (Figures 1 & 2).
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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.
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.
Figure 2. SARS-CoV-2 Spike (S) protein domains. Spike proteins have two subunits (S1, S2). In S1 subunit, the RBD (receptor binding domain) can bind to human ACE2 (Products 230-30165, 230-30177); CendR domain can bind to human NRP-1 b1b2 domain (Products 230-30176, 230-30178). The numbers below the domains show the amino acid position.
Thrombosis-related Protein Biomarkers
The inflammation associated with SARS-CoV-2 infection can cause disseminated intravascular coagulopathy (DIC), leading to obstruction of the blood vessels of lung, heart and kidneys. Initially, DIC in COVID-19 patients presents with abnormalities in prothrombin time, partial thromboplastin time, and platelet counts.
Angiotensin I Converting Enzyme 2 (ACE2) is an endogenous receptor that is required for SARS-CoV-2 viral entry. Neuropilin-1 (NRP1) assists in SARS-CoV-2 entry.
For help identifying the right protein for your research, please contact our technical support team at [email protected] or (888) 494-8555.
Analysis Images
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.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.
References
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A Shajahan, et al. Deducing the N- and O- glycosylation profile of the spike protein of novel coronavirus SARS-CoV-2. Glycobiology, cwaa042 (2020).
A Vojdani and D Kharrazian. Potential antigenic cross-reactivity between SARS-CoV-2 and human tissue with a possible link to an increase in autoimmune diseases. Clin Immunol. 217, 108480 (2020).
F Wu, et al. A new coronavirus associated with human respiratory disease in China. Nature. 579, 265–269 (2020).
J Yu, et al. Direct activation of the alternative complement pathway by SARS-CoV-2 spike protein is blocked by factor D inhibition. Blood. 2020 Sep 2;blood.2020008248 (2020).
M Casasanta, et al. Structural Insights of the SARS-CoV-2 Nucleocapsid Protein. Comput Struct Biotechnol J. 18, 2174–2184 (2020).
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).
M Norman, et al. Ultrasensitive high-resolution profiling of early seroconversion in patients with COVID-19. Nat Biomed Eng (2020).
M Woodruff, et al. Extrafollicular B cell responses correlate with neutralizing antibodies and morbidity in COVID-19. Nature Immunology (2020).
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).
P Nguyen-Contant, et al. S Protein-Reactive IgG and Memory B Cell Production after Human SARS-CoV-2 Infection Includes Broad Reactivity to the S2 Subunit. mBio. 11 (5) e01991-20 (2020).
W Li et al. Angiotensin-converting enzyme 2 is a functional receptor for the SARS coronavirus. Nature. 426, 450–454 (2003).