New study has revealed that the spike protein in coronavirus, which is used by the pathogen to latch onto the host’s cells, is more stable in the new variants of Covid-19.
The study stated that Covid-19 variants that were first reported in the United Kingdom and South Africa have more stable spike protein compared to the wild-type virus found in China in 2019.
For the study, researchers, including those from the Boston Children’s Hospital in the US, analysed in detail the structure of the coronavirus spike protein and its atomic level.
The study demonstrated how it changed with the D614G mutation which is carried by Brazil, South Africa and UK variants of the SARS-CoV-2 virus.
The findings revealed that the mutation makes the spike more stable. Thus, making the variants more contagious.
The authors stated in the study that the spike proteins in the original virus would bind to the ACE2 receptor on human cells. The proteins then dramatically change shape. They fold in on themselves and enable the pathogen to fuse its membrane with host cells.
However, they also noted that the spikes would sometimes prematurely change shape and fall apart before the virus could bind to cells. While this decelerates the virus, this process also helps the virus change its shape, making it more difficult for the human immune system to contain the virus.
“Because the original spike protein would dissociate, it was not good enough to induce a strong neutralizing antibody response,” said study co-author Bing Chen from the Boston Children’s Hospital.
The researchers further added that since these spikes are less apt to fall apart prematurely, the virus overall is rendered more infectious.
“Say the original virus has 100 spikes. Because of the shape instability, you may have just 50 per cent of them functional. In the G614 variants, you may have 90 per cent that are functional, so even though they don’t bind as well, the chances are greater that you will have the infection,” Chen said in the study.
The study was published in the journal Science.