Scientists at McGill University in Canada explained why older people are more vulnerable to the coronavirus SARS-CoV-2.
The researchers have analyzed the amino acid sequences of proteins involved in cell coronavirus infection. It turned out that coronavirus S-proteins and the ACE2 cell receptors interacting with them are rich in cysteine residues (Cys). Many cysteine residues remain common to various coronaviruses associated with SARS and participate in the formation of intramolecular disulfide bonds.
These two bonds have potential redox potential, which facilitates the primary interaction between the receptor and protein-bearing. This, in turn, enhances pathogenesis and contributes to the development of severe symptoms of COVID-19. Coronavirus-resistant animals do not have oxidation-reduction disulphide (Cys133-Cys141) in ACE2 sequences, which confirms the hypothesis about the oxidative nature of the virus pathogenicity.
Thus, increased cellular oxidation with age is the most likely explanation for the increased vulnerability of elderly people and people with concomitant diseases to COVID-19.