Scientists led by Professor of the University of Ulm Frank Kirchhoff have found a mutation in a key protein of the envelope of a new type of coronavirus, with the help of which SARS-CoV-2 binds to the membrane of human cells and penetrates into them.
During their work, the authors studied more than 1.7 million coronavirus samples: they compared their characteristic sets of mutations and highlighted in the structure of the RNA of the virus those variations that were characteristic of almost all varieties of SARS-CoV-2.
As a result, scientists drew attention to the T403R mutation: it was located in that part of the genome of the causative agent of COVID-19, which controls the production of a key element of its envelope, or S-protein.
The mutation is responsible for the penetration of the virus into the infected cell. When the S-protein binds to the ACE2 receptors on its surface and creates a hole in its membrane, the virus enters the cell through it.
The envelope proteins of the novel coronavirus and the raTG13 bat virus are very similar in structure, but the latter cannot effectively penetrate human cells. We have shown that when one point mutation appears in the genome, T403R, which is characteristic of virtually all strains of SARS-CoV-2.
During the experiment, a virus with such a mutation was able to enter human cells from a bat, while continuing to infect both humans and animals.