SARS-COV-2 (A222V MUTANT) SPIKE GLYCOPROTEIN (S1), SHEEP FC-TAG (HEK293)

SARS-CoV-2 Spike protein S1 containing A222V amino acid change. Increased transmissibility of the B.1.177 lineage may be associated with the presence of this mutation. SARS-CoV-2, previously known as the 2019 Novel Coronavirus (2019-nCoV), causes the pandemic COVID-19 disease.

PRODUCT DETAILS – SARS-COV-2 (A222V MUTANT) SPIKE GLYCOPROTEIN (S1), SHEEP FC-TAG (HEK293)

• SARS-CoV-2 A222V mutant Spike S1 protein (Acc. No. QLB39105.1, A222V, AA17-674)
• Expressed in HEK293 with sheep Fc-tag and purified by affinity chromatography.
• Presented in DPBS at greater than 95% purity.

BACKGROUND

Coronaviruses have a large genome and encode a 3′-to-5′-exoribonuclease that permits high-fidelity replication and a range of tolerated variation by the viral RNA-dependent RNA polymerase (Denison et al., 2011). This coronavirus exonuclease extends the coronavirus genome size through preventing lethal mutagenesis imposed by error rates of viral RNA polymerase (Smith et al., 2014). Therefore, SARS-CoV-2 could acquire rare but favorable mutations with fitness advantages and immunological resistance due to natural selection (Grubaugh et al., 2020) and a number of mutations to the SARS-CoV-2 genome have been observed throughout the COVID-19 pandemic (Erol, 2021).

2.58 million SARS-CoV-2 mutations in 200865 samples from 155 different countries (sequences downloaded from GISAID, 28 Dec 2020) were compared to the ancestral reference SARS-CoV-2 Wuhan strain showing that the most frequent nonsynonymous mutations were D614G and A222V, which occurred 176436 and 47971 times in the spike glycoprotein S gene (Ward et al., 2021). A222V is present in the 20A.EU1 SARS-CoV-2 ‘cluster’ (also designated as lineage B.1.177), which has been spreading in Europe and seems to have originated in Spain. Multiple introductions have occurred into the UK followed by transmission across the country, suggesting that this spread was likely associated with travel to/from Spain over the summer (COG-UK, 2020) and it has been speculated that the increased transmissibility of the B.1.177 lineage may be associated with the presence of this mutation. A222V is one of five amino acid replacements (D614G, A222V, N439K, Y453F and N501Y) investigated by The COVID-19 Genomics UK (COG-UK) Consortium. It is localized relatively far from the receptor-binding site in comparison with amino acid residues 453, 439 and 501, which are in the RBD region (COG-UK, 2020). The mutation is far from the main D614G mutation being located in the N-terminal domain of the S1 subunit. Both mutations D614G and A222V are located within areas defined as possible B-cell
epitopes which could provide to the virus an evasive immunological advantage to avoid B-cell response (Vilar & Isom, 2021).

REFERENCES

• COG-UK update on SARS-CoV-2 Spike mutations of special interest. Report 1. COG-UK, 19th December 2020.
• Denison M.R., Graham R.L., Donaldson E.F., Eckerle L.D., Baric R.S. Coronaviruses. RNA Biol. 2011;8:270–279.
• Erol A. Are the emerging SARS-COV-2 mutations friend or foe? Immunol Lett. 2021 Feb;230:63-64.
• Grubaugh N.D., Hanage W.P., Rasmussen A.L. Making sense of mutation: what D614G means for the COVID-19 pandemic remains unclear. Cell. 2020;182:794–795. 014;1:111–132.
• Smith E.C., Sexton N.R., Denison M.R. Thinking outside the triangle: replication fidelity of the largest RNA viruses. Annu. Rev. Virol.
• Vilar S, Isom DG. One Year of SARS-CoV-2: How Much Has the Virus Changed? Biology (Basel). 2021 Jan 26;10(2):91.
• Ward D, Higgins M, Phelan JE, Hibberd ML, Campino S, Clark TG. An integrated in silico immuno-genetic analytical platform provides insights into COVID-19 serological and vaccine targets. Genome Med. 2021 Jan 7;13(1):4.