Rio de Janeiro, Jan 5 (EFE) .- A group of Brazilian researchers identified one of the factors that increases the contagion potential of the British strain of covid-19, which is 70% more infectious than other variants, reported this Tuesday the Foundation for Research Support in the State of Sao Paulo (Fapesp).
The Brazilian researchers found that the spike protein of the new strain, which is the one that forms the structure of the corona that gives its name to the coronavirus family, has a greater force of molecular interaction with the ACE2 receptor, present on the surface of human cells and with which SARS-CoV-2 connects to initiate infection.
“The increase in the strength of molecular interaction of the new lineage is caused by an already identified mutation in amino acid residue 501 of the SARS-CoV-2 spike protein called N501Y, which gave rise to the new variant of the virus,” he explained. Fapesp in a note published on its portal.
The discovery was made by researchers at the University of Sao Paulo (USP) in a study funded by Fapesp and whose results were published on Tuesday on the international scientific platform bioRxiv in an article that has not yet been reviewed by other scientists.
The so-called British variant, baptized as B.1.1.7, has already been registered in a score of countries -including two cases in Brazil- and is characterized by a mutation that affects the way the virus fixes in human cells, which which makes it much more contagious.
“We found that the interaction between the spike protein of the new strain with the N501Y mutation is much greater than that presented by the first lineage of the virus that was isolated in Wuhan (China),” said Geraldo Aleixo Passos, researcher at USP and one of those responsible for the study.
“There are other mutations in the genome of the new lineage that we did not analyze. We focus on N501Y because it is involved in the connection of the spike protein with ACE2,” added Passos.
TESTING WITH PROTEIN STRUCTURES
To confirm their hypothesis, the researchers carried out tests with structures of the spike protein of the coronavirus isolated in Wuhan and with those of the present one in the British strain, as well as analysis with the public domain software PyMOL.
“The results of the analyzes showed that the mutation in the protein of the new variant establishes a greater interaction with the ACE2 receptor compared to the strain isolated in Wuhan,” explained Fapesp.
“The sum of several weak connections between the mutant spike protein and the human ACE2 receptor resulted in stronger molecular interactions, which allow the virus to more easily penetrate cells and deflagrate the replication system,” Passos said.
The study also revealed that the N501Y mutation causes an alteration in the distribution of the spaces between the amino acid residues of the spike protein, which allows it a greater interaction with the receptors in the human cell.
Although it has generated alarm in countries like the United Kingdom due to its high contagion capacity, so far there is no evidence that the British strain causes more serious cases of the disease, that it increases the mortality rate of the virus or that it is resistant to the existing vaccines.
Brazil, one of the countries most affected by the pandemic, last week identified its first two infected with the British strain.
Brazil is the second country with the most deaths from covid-19 in the world after the United States, with nearly 200,000 deaths, and the third with the most cases after the United States and India, with almost 7.8 million infections.
(c) EFE Agency