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Coronavirus- How the N439K variant escapes immune system’s antibodies

  • Posted By
    10Pointer
  • Categories
    Science & Technology
  • Published
    1st Feb, 2021

Context

  • Scientists have assessed a mutation in the novel coronavirus and found that it confers the virus resistance to some individual's serum antibodies.

What is the new variant and mutation?

  • Variants carrying this mutation are similar to the wild-type novel coronavirus from Wuhan, China in their ability to spread and cause disease.
  • They can bind more strongly to the human ACE2 receptor which acts as the gateway for the virus to enter host cells.
  • A single molecule part of the virus spike protein is altered from the amino acid asparagine to lysine, enabling the formation of a new point of contact with the ACE2 receptor.
  • This alteration takes place in the 439th position of the protein's chain of amino acid building blocks.
  • It is in line with a two-fold increase in its binding affinity with ACE2.

How the mutation is negative for immunity?

  • The mutation both improves interaction with the viral receptor ACE2 and evades antibody-mediated immunity
  • While the N439K mutation did not change virus replication, it significantly diminished binding of a proportion of both clinical antibodies and serum samples.
  • The mutation particularly resisted neutralization.

Mutation

  • A mutation is an alteration in the nucleotide sequence of the genome of an organism, virus, or extrachromosomal DNA.
  • Viral genomes contain either DNA or RNA.