A team of researchers has examined the reasons due to which the variants of SARS-CoV-2 originating from the UK and South Africa are more infectious and, in many cases, more deadly.
The study indicated that the UK variant, also known as B.1.1.7, has many mutations in the spike glycoprotein, but most importantly has one mutation, N501Y, in the receptor-binding domain that interacts with the ACE2 receptor.
“This N501Y mutation provides a much higher efficiency of binding, which in turn makes the virus more infectious,” said Victor Padilla-Sanchez, a scientist at The Catholic University of America.
The United Kingdom variant was first detected in September 2020 and is now responsible for 98 per cent of all COVID-19 cases in the UK.
The World Health Organization (WHO) said the UK variant is one of several variants that raise concern, along with others that have emerged in South Africa and Brazil.
The coronavirus variant that emerged in South Africa in October 2020 has even more important changes in the spike protein, making it more dangerous than the UK variant.
According to the researchers, it involves a key mutation, called E484K, that helps the virus evade antibodies and parts of the immune system that can fight coronavirus based on experience from prior infection or a vaccine.
Since the variant escapes from the response of the immune system, the body will not be able to fight the virus, the team said.
All three variants have undergone changes to their spike protein that is the part of the virus which attaches to human cells. As a result, they are better at infecting cells and spreading them.
In the study, which was published in the journal Research Ideas and Outcomes, the team presented a computational analysis of the structure of the spike glycoprotein bound to the ACE2 receptor where the mutations have been introduced.