Delta and Omicron, the current SARS-CoV-2 variants, have spike-like projections that attach themselves to human cells faster, longer, and stronger.
As part of a publication in the journal "Nature Communications", JKU researchers are reporting that this distinguishes these variants from Coronavirus variants seen at the beginning of the pandemic. The pathogens are absorbed more quickly and airflow, mucus, or blood flow are less likely to easily detached then from the host cells.
A team led by Peter Hinterdorfer (Institute of Biophysics, JKU) analyzed just how Coronavirus spikes attach to human cell surfaces by using atomic force microscopy and computer simulations. The researchers reported that the spikes (made up from three identical components) rapidly change shape once they attach to ACE2 proteins on the cell surface. As a result, their grasping zones (receptor binding domains) rotate in an arcuate motion and together, they cover almost an entire circular area of 360 degrees.
The researchers explained: "Its highly dynamic, molecular grip forms up to three tight bonds with ACE2 on the cell surface." Compared to the original variant (Wuhan-1), the spikes on the Delta and Omicron variants bind the virus significantly stronger and longer to the host cell’s ACE2 molecules. Most notably, the Delta variant adheres faster, and Omicron ten times longer.
The research team, which includes Austrian molecular biologist Josef Penninger (head the Life Sciences Institute (LSI) at the University of British Columbia in Vancouver, Canada), noted that the shift in binding dynamics among currently circulating variants increases their virulence and viral transmission.
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