Overview:

The receptor binding domain (RBD) of the SARS-CoV-2 spike glycoprotein recognizes the host ACE2 receptor and is a major determinant of viral entry and neutralization (1). At the end of 2021, the IHU variant, a new Pangolin lineage B.1.640.2, emerged in southeastern France, possessing 30 amino acid substitutions and 12 deletions (2). The IHU variant possesses substitutions N501Y and E484K, which are also present in the Beta, Gamma, Theta and Omicron variants (2). The F490S substitution is also present in the Lambda variant (2). Several of the detected mutations were predicted to significantly affect neutralizing epitopes (2). As new variants displace the first-wave virus, it is pivotal to evaluate their transmissibility, virulence and their possible tendency to escape antibody neutralization (3).

Gene Aliases:

2019-nCoV RBD, SARS-CoV-2 spike RBD, novel coronavirus spike RBD, nCoV spike RBD.

Genbank Number:

MN908947

References:

1. Lan J, et al: Crystal structure of the 2019-nCov spike receptor-binding domain bound with the ACE2 receptor. bioRxiv. doi: https://doi.org/10.1101/2020.02.19.956235.

2. Colson, P. et al. Emergence in Southern France of a new SARS-CoV-2 variant of probably Cameroonian origin harbouring both substitutions N501Y and E484K in the spike protein. medRxiv 2021; https://www.medrxiv.org/content/10.1101/2021.12.24.21268174v1.full.pdf

3. Starr TN, et al: Molecular dynamic simulation reveals E484K mutation enhances spike RBD-ACE2 affinity and the combination of E484K, K417N and N501Y mutations (501Y.V2 variant) induces conformational change greater than N501Y mutant alone, potentially resulting in an escape mutant. Cell. 2020, 182(5):1295-1310.