Welcome! If we look down to the floor, we can visualize the evolutionary tree of this spike protein, and the various branches indicate the subtle but important mutations DNA in the protein along the way.
For example let’s look closely at this spike protein coming from a Coronavirus that can infect bats. Recent studies have shown that it is very similar to the neighboring spike protein (on right) originating from the SARS-COV2 virus causing the pandemic.
There are few critical differences between these spike proteins, for example you can see them highlighted in colors and it is these changes that allow the Coronavirus to successfully infect humans. These modifications or adaptations in the spike protein are very crucial. An enzyme called Furin can recognize these sites and activate the spike protein for a better attachment to the human cells. This attachment is possible via binding of the spike protein to the human ACE-2 receptor.
Recent studies from the scientific community have demonstrated that blocking spike protein-mediated attachment (eg: via antibodies) can be a successful strategy to prevent infection and also strengthen the immune response of patients against the Coronavirus.