Never ending story? Evolution of SARS-CoV-2 monitored through Gibbs energies of biosynthesis and antigen-receptor binding of Omicron BQ.1, BQ.1.1, XBB and XBB.1 variants

Abstract

RNA viruses exhibit a great tendency to mutate. Mutations occur in the parts of the genome that encode the spike glycoprotein and less often in the rest of the genome. This is why Gibbs energy of binding changes more than that of biosynthesis. Starting from 2019, the wild type that was labeled Hu-1 has during the last 3 years evolved to produce several dozen new variants, as a consequence of mutations. Mutations cause changes in empirical formulas of new virus strains, which lead to change in thermodynamic properties of biosynthesis and binding. These changes cause changes in the rate of reactions of binding of virus antigen to the host cell receptor and the rate of virus multiplication in the host cell. Changes in thermodynamic and kinetic parameters lead to changes in biological parameters of infectivity and pathogenicity. Since the beginning of the COVID-19 pandemic, SARS-CoV-2 has been evolving towards increase in infectivity and maintaining constant pathogenicity, or for some variants a slight decrease in pathogenicity. In the case of Omicron BQ.1, BQ.1.1, XBB and XBB.1 variants pathogenicity is identical as in the Omicron BA.2.75 variant. On the other hand, infectivity of the Omicron BQ.1, BQ.1.1, XBB and XBB.1 variants is greater than those of previous variants. This will most likely result in the phenomenon of asymmetric coinfection, that is circulation of several variants in the population, some being dominant.

Keywords: Binding affinity; COVID-19; Elemental composition; Thermodynamic property; Variant of concern (VOC); Virus-host interaction.

Graphical abstract

Fig. 1

Time evolution of SARS-CoV-2 variants through standard Gibbs energies of biosynthesis. This time shows standard Gibbs energy of biosynthesis, Δ_bsG⁰, of various SARS-CoV-2 variants, which appeared at different times.

Fig. 2

Time evolution of SARS-CoV-2 variants through standard Gibbs energies of binding. This time shows standard Gibbs energy of binding, Δ_BG⁰, of various SARS-CoV-2 variants, which appeared at different times.