Allosteric Cross-Talk among Spike's Receptor-Binding Domain Mutations of the SARS-CoV-2 South African Variant Triggers an Effective Hijacking of Human Cell Receptor

The rapid and relentless emergence of novel highly transmissible SARS-CoV-2 variants, possibly decreasing vaccine efficacy, currently represents a formidable medical and societal challenge. These variants frequently hold mutations on the Spike protein's receptor-binding domain (RBD), which, binding to the angiotensin-converting enzyme 2 (ACE2) receptor, mediates viral entry into host cells. Here, all-atom molecular dynamics simulations and dynamical network theory of the wild-type and mutant RBD/ACE2 adducts disclose that while the N501Y mutation (UK variant) enhances the Spike's binding affinity toward ACE2, the concomitant N501Y, E484K, and K417N mutations (South African variant) aptly adapt to increase SARS-CoV-2 propagation via a two-pronged strategy: (i) effectively grasping ACE2 through an allosteric signaling between pivotal RBD structural elements and (ii) impairing the binding of antibodies elicited by infected or vaccinated patients. This information unlocks the molecular terms and evolutionary strategies underlying the increased virulence of emerging SARS-CoV-2 variants, setting the basis for developing the next-generation anti-COVID-19 therapeutics.

Automated summary

The emergence of novel highly transmissible SARS-CoV-2 variants poses a formidable challenge to vaccine efficacy, with mutations on the RBD/ACE2 binding facilitating viral entry into host cells. Some variants increase transmission by enhancing ACE2 binding affinity and impairing antibody recognition, revealing molecular and evolutionary strategies behind their increased virulence for future anti-COVID-19 therapeutics.