Scientists estimate that the virus had infected 550 million people and killed 50-100 million.
French biologists from Nantes University to find out why the Spanish flu pandemic (“Spanish flu”) has led to numerous victims. It turned out that the cause is a mutation that changes one amino acid in the hemagglutinin (eng. HA) — a protein that provides the ability of the virus to contact the cell. Their findings are presented in the Preprint, published in the repository arXiv.org.
The researchers analyzed the amino acid sequence of HA, which were isolated from virus in lung tissue samples of a man who died in 1918. These sequences were compared with other contained in a database of the National center for biotechnology information (NCBI).
It was carried out pairwise alignment, in which each amino acid in the hemagglutinin of the “Spanish flu” aligned the amino acid at the same position of the other protein. For this purpose, the scientists have used the program BLAST, which finds similarities and differences in the sequences of related proteins and nucleic acids (DNA and RNA).
It is established that the hemagglutinin of 1918 different from other proteins 25 amino acids. One of which is glycine in the 188th position is located in the key area of the molecule, ensuring the adherence to the surface of infected cells. Such a feature is rare in the HA molecules of other viruses, so, according to scientists, it is the cause of the lethality of the Spanish flu.
The researchers hope that monitoring of mutations in the hemagglutinin of different influenza strains will help to identify new deadly viruses.
“Spanish flu” — a massive flu epidemic that occurred in 1918-1919. Scientists estimate that the virus had infected 550 million people and killed 50-100 million.
