CORONAVIRUS AND COVID-19 PANDEMIC
Scientists intrigued by new SARS-CoV-2 mutations
The announcement by the British Minister for Health of the abundance of a variant in the south of England has rekindled speculation about the possible emergence of more virulent strains and refractory to vaccination.
S.D614G, S.N501Y, S.N439K, S.H69 / V70, S.S477N… These strange codes are watched like milk on fire by virologists. They refer to parts of a key protein of the virus responsible for Covid-19, the spicule, which gives SARS-CoV-2 this spiky shape and thanks to which it attaches to human cells before infecting them.
It is also the molecule on which the action of vaccines which "mimic" is based to stimulate the production of antibodies. So any change in this protein could alter the behavior of the virus towards greater infectivity or virulence. Or even reduce the effectiveness of vaccines.
Proof of the sensitive nature of the question, Monday, December 14, a statement by the British Minister for Health, Matt Hancock, worried: a new viral line would have been detected with a greater frequency in the country. Immediately, the COG-UK consortium (Covid Genomics Consortium), which in turn sequences genomes of the virus, “opened an investigation” into this mysterious strain. It has more than a dozen mutations, including at least two on the famous spicule.
For a year, the virus has changed little
One of these mutations is a change of the 501st amino acid of the 1,273 that makes up the protein, in the area that is used for attachment to cells. In the Gisaid database, which collects genomes from around the world in order to make them available to researchers, there are already more than 2,000 that present this variant (out of 267,600 sequences listed). The other mutation is the absence of the 69th and 70th amino acids. These are not involved in binding, but this change is likely to alter the spatial shape of the protein and thus potentially induce new effects. A total of 4,916 similar sequences are already present in Gisaid.
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