SARS-CoV-2 Delta (B.1.617.2) Variant: A Unique T478K Mutation in Receptor Binding Motif (RBM) of Spike Gene

Over two hundred twenty-eight million cases of coronavirus disease 2019 (COVID-19) in the world have been reported until the 21st of September 2021 after the first rise in December 2019. The virus caused the disease called severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Over 4 million deaths blame COVID-19 during the last one year and 8 months in the world. Currently, four SARS-CoV-2 variants of concern are mainly focused by pandemic studies with limited experiments to translate the infectivity and pathogenicity of each variant. The SARS-CoV-2 alpha, beta, gamma, and delta variant of concern was originated from United Kingdom, South Africa, Brazil/Japan, and India, respectively. The classification of SARS-CoV-2 variant is based on the mutation in spike (S) gene on the envelop of SARS-CoV-2. This review describes four SARS-CoV-2 alpha, beta, gamma, and delta variants of concern including SARS-CoV-2 epsilon, zeta, eta, iota, kappa, and B.1.617.3 variants of interest and alert. Recently, SARS-CoV-2 delta variant prevails over different countries that have 3 unique mutation sites: E156del/R158G in the N-terminal domain and T478K in a crucial receptor binding domain. A particular mutation in the functional domain of the S gene is probably associated with the infectivity and pathogenesis of the SARS-CoV-2 variant.

Automated summary

As of September 21, 2021, over 228 million cases of COVID-19 have been reported worldwide, resulting in over 4 million deaths. The predominant circulating variants of concern are alpha, beta, gamma, and delta, originating from different countries like the UK, South Africa, Brazil/Japan, and India, respectively. These variants exhibit unique mutations in the spike gene, which may impact their infectivity and pathogenicity.