RBD (K417N, E484K, N501Y) (319-541)—the recombinant 2019-nCoV spike protein S1 subunit—was expressed in CHO cells through a C-terminal His tag.
The protein purity was found to be about 90% by densitometry, with a molecular weight of 39 kDa. With the help of a functional ELISA, users can detect the activity by analyzing the binding ability of the 2019-nCoV Spike protein RBD (K417N, E484K and N501Y) to the immobilized human ACE2 (19-740) protein.
The host ACE2 receptor is detected by the receptor-binding domain (RBD) of the SARS-CoV-2 spike glycoprotein. The RBD is a crucial determinant of the entry and neutralization of a virus.1 The SARS-CoV-2 (501Y.V2 variant) with mutations at the main locations in RBD (N501, E484K and K417N) has adversely affected the areas of South Africa.2
MD simulation denotes that the combination of N501Y, E484K and K417N leads to the highest degree of conformational changes of RBD when attached to hACE2, in comparison with either N501Y or E484K alone.
Both N501Y and E484K increase the affinity of RBD for hACE2, and the charge switch caused by E484K leads to the formation of conducive contacts. As the first-wave virus is displaced by new variants, it is crucial to assess their virulence, transmissibility and also their potential tendency to evade antibody neutralization.3
Binding ability measured in a functional ELISA. 2019-nCoV spike protein RBD (K417N, E484K, N501Y) binds to immobilized human ACE2 (19-740) protein (A51C2-G341F). Image Credit: SignalChem Biotech Inc.
- 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.
- Houriiyah T, et al: Emergence and rapid spread of a new severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) lineage with multiple spike mutations in South Africa. medRxiv 2020; doi: https://doi.org/10.1101/2020.12.21.20248640
- 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.