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SARS-CoV-2 Nucleocapsid (N) protein

The Nucleocapsid Protein (N-protein), also called coronavirus nucleocapsid (N), is the most abundant protein in coronavirus. It is a structural protein that forms complexes with genomic RNA, interacts with the viral membrane protein during virion assembly and plays a critical role in enhancing the efficiency of virus transcription and assembly.

N-protein is a highly immunogenic phosphoprotein, and it is normally very conserved. It contains 419 amino acids in length.

Available peptide libraries

Some proteins of Sars-CoV-2 are identified as leading targets for COVID-19 therapies. sb-PEPTIDE offers pre-made peptide libraries of Nucleocapsid protein and can custom synthesize specific libraries (including sequences with phosporylated amino acids).

Nucleocapsid protein – peptide library – Reference #SB044

Coronavirus Nucleocapsid (N) is a phosphoprotein of 419 aa length. sb-PEPTIDE offers a library of 102 peptides with a length of 15 amino acids and an overlap of 11 amino acids (without post-translational modification).

Nucleocapsid protein – biotinylated peptide library – Reference #SB044-biotin

The above library is available with N-ter biotin.

 Technical specifications

SARS-CoV-2 Nucleocapsid (N) protein buy Peptides length : 15 aa
SARS-CoV-2 Nucleocapsid (N) protein buy peptide library Offset number : 11 aa
SARS-CoV-2 Nucleocapsid (N) protein peptide library Amount : 0,5mg or 5*0,5mg (for each peptide)
SARS-CoV-2 Nucleocapsid (N) protein price Quality : Crude, 100% LC-MS
SARS-CoV-2 Nucleocapsid (N) protein synthesis Counter-Ion : TFA Salts (see option TFA removal)
Peptide library synthesis SARS-CoV-2 Nucleocapsid (N) protein Delivery format : Lyophilized or in solution, in 96-well plate or microtubes
SARS-CoV-2 Nucleocapsid (N) protein peptide library buy Price : Ask for your quote
SARS-CoV-2 Nucleocapsid (N) protein standard solubility guidelines Peptide Solubility Guideline



1- Sisi Kang et al. Acta Pharmaceutica Sinica B. (2020)
Crystal structure of SARS-CoV-2 nucleocapsid protein RNA binding domain reveals potential unique drug targeting sites




The outbreak of coronavirus disease (COVID-19) in China caused by the SARS-CoV-2 virus continually lead to worldwide human infections and deaths. It is currently no specific viral protein targeted therapeutics. Viral nucleocapsid protein is a potential antiviral drug target, serving multiple critical functions during the viral life cycle. However, the structural information of the SARS-CoV-2 nucleocapsid protein remains unclear.


To obtain the structural information of the SARS-CoV-2 nucleocapsid protein, we have determined the 2.7 Å crystal structure of the N-terminal RNA binding domain of SARS-CoV-2 nucleocapsid protein using X-ray crystallography technology. To explored the interaction mechanism, we complemented functional studies by in vitro surface plasmon resonance analysis and biolayer interferometry assays.


Although the overall structure is similar to other reported coronavirus nucleocapsid protein N-terminal domain, the surface electrostatic potential characteristics between them are distinct. Further comparison with mild virus type HCoV-OC43 equivalent domain demonstrates a unique potential RNA binding pocket alongside the β-sheet core.


Our data provide several atomic resolution features of the SARS-CoV-2 nucleocapsid protein N-terminal domain, guiding the design of novel antiviral agents specific targeting to SARS-CoV-2.

2- Noton K et al. Gordy Journal of Virology. (2020)
The Nucleocapsid Protein of SARS–CoV-2: a Target for Vaccine Development


During the current coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS–CoV-2), there has been an unprecedented level of global collaboration that has led to a rapid characterization of SARS–CoV-2 (1). Its sequence shares 79.6% identity to SARS–CoV (1, 2), the infectious virus that caused an epidemic in 2003 (2, 3). SARS–CoV-2 has a single-stranded, plus-sense, RNA genome of approximately 30 kb, which includes five major open reading frames encoding nonstructural replicase polyproteins and structural proteins (1), namely, spike (S) (46), envelope (E), membrane (M), and nucleocapsid (N) (7), and they are in the same order and of approximately the same sizes as those in SARS-CoV.

The SARS–CoV-2 S protein is being used as the leading target antigen in vaccine development (8, 9). However, the complex molecular details of viral entry may lead to complications with the vaccine response, similar to those seen with HIV type 1 (HIV-1) Env protein vaccine efforts (10). The SARS–CoV-2 S gene has 76% amino acid similarity to the SARS-CoV S gene (11), and nonsynonymous mutations developed in the S protein as the SARS-CoV epidemic progressed (12, 13). In contrast, the N gene is more conserved and stable, with 90% amino acid homology and fewer mutations over time (2, 3, 11, 1416). N proteins of many coronaviruses are highly immunogenic and are expressed abundantly during infection (17). High levels of IgG antibodies against N have been detected in sera from SARS patients (18), and the N protein is a representative antigen for the T-cell response in a vaccine setting, inducing SARS-specific T-cell proliferation and cytotoxic activity (19, 20). We have already shown that the middle or C-terminal region of the SARS-CoV N protein is important for eliciting antibodies against SARS-CoV during the immune response (2123).

New reports have additionally shown that the crystal structure of the SARS–CoV-2 nucleocapsid protein is similar to those of previously described coronavirus N proteins, but their surface electrostatic potential characteristics are distinct (7). Sheikh et al. studied the factors influencing N gene variations among 13 coronaviruses and how these affect virus-host relationships, reporting a high AT% and low GC% in the nucleotide contents of SARS coronavirus (24). In this issue, Cong et al. (17) used a mouse hepatitis virus (MHV) model to show that the viral nucleocapsid (N) protein contributes to forming helical ribonucleoproteins during the packaging of the RNA genome, regulating viral RNA synthesis during replication and transcription and modulating metabolism in infected subjects. This study complements others that have shown N to have multiple functions (25). It is becoming more evident just how critical this protein is for multiple steps of the viral life cycle. These reports offer important and timely insights relevant to the SARS–CoV-2 N protein, a vaccine target that has some distinct advantages over other potential SARS–CoV-2 antigens. Because of the conservation of the N protein sequence, the expanding knowledge of its genetics and biochemistry, and its strong immunogenicity, the N protein of SARS–CoV-2 should be strongly considered as a vaccine candidate for SARS–CoV-2.

3- Bruno Tilocca et al. Microbes and Infection, Volume 22. (2020)
Comparative computational analysis of SARS-CoV-2 nucleocapsid protein epitopes in taxonomically related coronaviruses



Several research lines are currently ongoing to address the multitude of facets of the pandemic COVID-19. In line with the One-Health concept, extending the target of the studies to the animals which humans are continuously interacting with may favor a better understanding of the SARS-CoV-2 biology and pathogenetic mechanisms; thus, helping to adopt the most suitable containment measures. The last two decades have already faced severe manifestations of the coronavirus infection in both humans and animals, thus, circulating epitopes from previous outbreaks might confer partial protection from SARS-CoV-2 infections. In the present study, we provide an in-silico survey of the major nucleocapsid protein epitopes and compare them with the homologues of taxonomically-related coronaviruses with tropism for animal species that are closely inter-related with the human beings population all over the world. Protein sequence alignment provides evidence of high sequence homology for some of the investigated proteins. Moreover, structural epitope mapping by homology modelling revealed a potential immunogenic value also for specific sequences scoring a lower identity with SARS-CoV-2 nucleocapsid proteins. These evidence provide a molecular structural rationale for a potential role in conferring protection from SARS-CoV-2 infection and identifying potential candidates for the development of diagnostic tools and prophylactic-oriented strategies.