Spike protein shape shifter
While the UK variant was first detected in September, officials noticed that it was rapidly spreading through the country in mid-December, leading to tighter restrictions on movement and businesses
within days. South African officials
reported on December 18 that 501.V2 had been largely replacing other strains of the coronavirus as early as November.
501.V2 carries a mutation in the spike protein called E484K, which is not present in the UK strain, Francois Balloux, the director of the University College London Genetics Institute, says in a
statement. “The E484K mutation has been shown to reduce antibody recognition,” he says, which may help the virus bypass immune protection provided by prior infection or vaccination. However, he says that the mutation is not sufficient for the variant to bypass the protection provided by vaccines.
South African SARS-CoV-2 Variant Alarms Scientists
Dr Julian W Tang, Honorary Associate Professor/Clinical Virologist at the University of Leicester, said:
“The South African variant (B.1.351 or 501Y.V2) differs significantly from the UK B.1.1.7(variant) in several ways that may impact on vaccine effectiveness.
expert reaction to the South African variant | Science Media Centre
“Both variants share the N501Y mutation in the viral S gene which lies in the receptor binding domain (RBD) – where the virus binds to the host cell – and where vaccine-induced antibodies bind to the virus. But the South African variant has two more mutations – E484K and K417N – in this RBD region that are absent in the UK variant. These two additional mutations may interfere more with vaccine effectiveness in the South African variant than in the UK variant.
“This does not mean that the existing COVID-19 vaccines will not work at all, just that the antibodies induced by the current vaccines may not bind and neutralise the South African variant as well as it would the other circulating viruses – including the UK variant.