The Omicron variant has an unprecedented 36 mutations on its spike protein, three to five times more than previous variants.
Structural analysis revealed that several mutations create new salt bridges and hydrogen bonds between the spike protein and the human cell receptor known as ACE2.
The new bindings appear to increase binding affinity – the strength with which the virus attaches to human cells.
“The results show that Omicron has greater binding affinity than the original virus, with levels more comparable to what we see with the Delta variant,” Subramaniam said.
“It is remarkable that the Omicron variant has evolved to retain its ability to bind to human cells despite such large mutations.”
The Omicron spike protein exhibits enhanced antibody evasion.
Unlike previous variants, Omicron showed measurable breakout of all six monoclonal antibodies tested, with complete breakout of five.
The variant also showed increased evasion of antibodies collected from vaccinated individuals and unvaccinated Covid-19 patients.
“Notably, Omicron was less evasive of immunity created by vaccines, compared to immunity against natural infection in unvaccinated patients. This suggests that vaccination remains our best defense,” Subramaniam informed.