Coronaviruses (CoVs) are a large group of viruses that commonly originate in many different species of animals. Some coronaviruses can make a jump from animals to human, and cause the respiratory infections including mild and cold-like symptoms. A couple of coronaviruses including Middle East respiratory syndrome (MERS) and severe acute respiratory syndrome (SARS), are much more severe and have killed thousands of people.
2019-nCoV, officially named as SARS-CoV-2, is another contagious and novel coronavirus that can infect people and cause outbreak of respiratory illness (COVID-19). It was first detected in Wuhan, China in December, 2019, and is being reported in a growing number of international locations. The rapid person-to-person spread of SARS-CoV-2 presents a imminent threat to the global public health. It was declared as pandemic by WHO on March 11th 2020. As of Jan 15, 2021, over 93,630,000 COVID-19 cases caused by SARS-CoV-2 have been recorded worldwide, and more than 2,004,400 people have been reported dead.
Chinese health authorities were the first to isolate the SARS-CoV-2, the Wuhan seafood market pneumonia virus isolate Wuhan-Hu-1, and published the full genome sequence of the 2019-nCoV which is ~90% of nucleotide similarity to a group of SARS-like coronaviruses. Protein sequence analysis revealed that 2019-nCoV shares ~80% sequence identity to SARS-CoV, and 96% identity to a bat coronavirus at the whole-genome level. US CDC has also posted the full genome of the SARS-CoV-2 viruses detected in U.S. patients, and found the sequences from US patients similar to the one that China initially posted.
Like MERS and SARs, SARS-CoV-2 are also large, enveloped, positive-sense, single-stranded RNA viruses. The genome of coronavirus encodes four major structural proteins including Spike (S) protein, Nucleocapsid (N) protein, Envelope (E) protein, and Membrane (M) protein, as well as a number of accessory open reading frame (ORF) proteins.
The coronavirus Nucleocapsid (N) is a structural protein of multifunction. The N protein of CoVs forms the helical ribonucleocapsid complexes with positive strand viral genomic RNA, and interacts with viral membrane protein during virion assembly, and plays an important role in enhancing the efficiency of virus replication, transcription, and assembly.
The coronavirus Spike protein (S) is a large oligomeric transmembrane protein that mediates coronavirus entry into host cells. It contains S1 and S2 two subunits. Spike S1 mainly contains a receptor binding domain (RBD) that recognizes a variety of host cell surface receptors. S2 contains basic elements responsible for the membrane fusion. The coronavirus first binds to a receptor on the host cell surface through Spike S1 subunit, and then fuses viral and host membranes through Spike S2 subunit.
Structural modelling studies of Spike proteins from SARS-CoV-2 and SARS-CoVs suggests that the SARS-CoV-2 S protein retains sufficient affinity to the cellular Angiotensin converting enzyme 2 (ACE2) protein, and likely uses ACE2 protein as a receptor for cellular entry. Most recent study(4) shows that the 2019-nCoV S's affinity to bind to ACE2 is 10-20 fold higher than that of SARS-CoV S.
To contribute to the global effort of combating the virus, EUPROTEIN developed a series of SARS-CoV-2 antigens and the associated cellular receptor proteins. These high-quality proteins are all expressed in Human cell, can be used for basic research study of 2019-nCoVs, and would also help in potential diagnostic and therapeutic developments for the SARS-CoV-2 and related COVID-19 diseases.
If you need help in expressing the SARS-CoV-2 (2019-nCoV) proteins to generating antibodies against them, or to develop any particular assays for the detection of viruses, please submit your inquiry.
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