SARS-CoV-2 RBD of Spike protein, E484Q, L452R – lineage B.1.617 – Indian Kappa Variant

Description of SARS-CoV-2 RBD of Spike protein, E484Q, L452R – lineage B.1.617 – Indian Variant

General information on SARS-CoV-2 RBD of Spike protein, E484Q, L452R – lineage B.1.617 – INDIAN Variant

Lineage B.1.617, also known as the Indian variant, has been named variant under investigation (VUI) by the Public Health England (PHE) at the beginning of April 2021. This variant was first reported in India at the end of March 2021 and it could be responsible for the third wave of COVID-19 in that region. However, B.1.617 may have originated much earlier because the first genome of this lineage was submitted to the global database (GISAID) as early as October 2020. Since then, the variant has shown a sustained spread across India reaching a relative abundance of 33% during April. Moreover, it has also been detected in other countries, namely in the UK and the US (February 2021) where it continues to spread unattained. This variant carries two important mutations on the receptor-binding domain (RBD) of the spike protein – E484Q and L452R. These two mutations have been previously described in other SARS-CoV-2 variants and are known to confer immune escape and to increase infectivity. Nevertheless, this is the first time the two RBD mutations are detected on the same lineage of SAR-CoV-2 which is often referred to as a “double mutant.”
The L452R amino acid change has been reported in another high-frequency lineage – B.1.429 first detected in California, US. While the amino acid change on position E484 has been reported on the South African (B.1.351), Brazilian (P.1), and NY variants (B.1.526) all shown to carry mutation E484K (instead of E484Q). Besides these mutations, B.1.617 carries 11 additional mutations that result in amino acid changes, including spike mutation P681R outside of the RBD, which is located adjacent to the furin cleavage site of the spike suggesting it might influence the way the spike is processed during infection.
Studies with B.1.617 will be crucial to understand how these mutations will affect vaccine and drug efficiency for the prevention and treatment of the COVID-19 disease.

SDS-PAGE for SARS-CoV-2 RBD of Spike protein, E484Q, L452R – lineage B.1.617 – Indian Kappa Variant