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Description: Coronavirus disease 2019 (COVID-19), formerly known as 2019-nCoV acute respiratory disease, is an infectious disease caused by SARS-CoV-2, a virus closely related to the SARS virus (1). The disease is the cause of the 2019–20 coronavirus outbreak (2). The structure of 2019-nCoV consists of the following: a Spike protein (S), hemagglutinin-esterease dimer (HE), a membrane glycoprotein (M), an envelope protein (E) a nucleoclapid protein (N) and RNA. Coronavirus invades cells through Spike (S) glycoproteins, a class I fusion protein. It is the major viral surface protein that coronavirus uses to bind to the human cell surface receptor. It also mediates the fusion of host and viral cell membrane, allowing the virus to enter human cells and begin infection (3). The spike protein is the major target for neutralizing antibodies and vaccine development (4). The protein modeling suggests that there is strong interaction between Spike protein receptor-binding domain and its host receptor angiotensin-converting enzyme 2 (ACE2), which regulate both the cross-species and human-to-human transmissions of COVID-19 (5). The recent study has shown that the SARS-CoV-2 spike protein binds ACE2 with higher affinity than SARS-CoV spike protein (6).

Description: Coronavirus disease 2019 (COVID-19), formerly known as 2019-nCoV acute respiratory disease, is an infectious disease caused by SARS-CoV-2, a virus closely related to the SARS virus (1). The disease is the cause of the 2019–20 coronavirus outbreak (2). The structure of 2019-nCoV consists of the following: a Spike protein (S), hemagglutinin-esterease dimer (HE), a membrane glycoprotein (M), an envelope protein (E) a nucleoclapid protein (N) and RNA. Coronavirus invades cells through Spike (S) glycoproteins, a class I fusion protein. It is the major viral surface protein that coronavirus uses to bind to the human cell surface receptor. It also mediates the fusion of host and viral cell membrane, allowing the virus to enter human cells and begin infection (3). The spike protein is the major target for neutralizing antibodies and vaccine development (4). The protein modeling suggests that there is strong interaction between Spike protein receptor-binding domain and its host receptor angiotensin-converting enzyme 2 (ACE2), which regulate both the cross-species and human-to-human transmissions of COVID-19 (5). The recent study has shown that the SARS-CoV-2 spike protein binds ACE2 with higher affinity than SARS-CoV spike protein (6).

Description: Recombinant COVID-19 (2019 novel coronavirus) Spike protein (S1+S2 ECD) was fused to His-tag at C-terminus and expressed in Baculovirus-Insect cell. The spike (S) glycoprotein of coronaviruses contains protrusions that will only bind to certain receptors on the host cell.S1 mainly contains a receptor binding domain (RBD) and recognize the cell surface receptor. S2 essential for membrane fusion. S protein are important for neutralizing-antibody and T-cell responses, as well as protective immunity.

Description: Severe acute respiratory Coronavirus Spike trimer (S1+S2), with 682-685>A, K986P, V987P, and D614G mutations, Genbank Accession No. MN908947, a.a. 1-1213, with a C-terminal His-tag, expressed in a HEK293 expression system. MW=137 kDa. This protein runs at a higher M.W. by SDS-PAGE due to glycosylation.

Description: SARS-CoV-2 (COVID-19) Spike S2 ECD Recombinant Protein

Description: Severe acute respiratory Coronavirus Spike trimer (S1+S2), Genbank Accession No. MN908947, a.a. 16-1213, with a with C-terminal His-tag, Eu-labeled, expressed in a HEK293 expression system. MW=139 kDa. This protein runs at a higher M.W. by SDS-PAGE due to glycosylation.

Description: Recombinant SARS-CoV-2 Spike protein in its homotrimeric form, containing S1+S2 subunits and encompassing amino acids 16-1213. This protein corresponds to SARS-CoV-2 Variant B.1.351, also known as variant Beta originally discovered in South Africa, and contains the nine known mutations listed below, in addition to deletion 242-244. It also contains mutations 682RRAR685>A, K986P and V987P. The construct has a C-terminal His-tag (6xHis). Note that the expected MW of the S1+S2 monomer is 137kDa but migrates at a higher MW in SDS-PAGE due to glycosylation. The recombinant protein was affinity purified.

*Deletion 242-244 is known as 241-243 in some databases and on the CDC website. This is the same deletion. As stated by Tegally et al., Nature 2021: "We also observe a deletion of three amino acids at positions 242 to 244, which was seen in samples extracted and generated in different laboratories across the NGS-SA. This region is difficult to align; the deletion could potentially also be located at positions 241 to 243, but the resulting sequence would be exactly the same. "

Description: A human infecting coronavirus (viral pneumonia) called 2019 novel coronavirus, 2019-nCoV was found in the fish market at the city of Wuhan, Hubei province of China on December 2019. The 2019-nCoV shares an 87% identity to the 2 bat-derived severe acute respiratory syndrome 2018 SARS-CoV-2 located in Zhoushan of eastern China. 2019-nCoV has an analogous receptor-BD-structure to that of 2018 SARS-CoV, even though there is a.a. diversity so thus the 2019-nCoV might bind to ACE2 receptor protein (angiotensin-converting enzyme 2)  in humans. While bats are possibly the host of 2019-nCoV, researchers suspect that animal from the ocean sold at the seafood market was an intermediate host. RSCU analysis proposes that the 2019-nCoV is a recombinant within the viral spike glycoprotein between the bat coronavirus and an unknown coronavirus.