The binding of a SARS-CoV-2 virus surface protein spike—a projection from the spherical virus particle—to the human cell surface protein ACE2 is the first step to infection that may lead to COVID-19 disease. Penn State researchers computationally assessed how changes to the virus spike makeup can affect binding with ACE2 and compared results to those of the original SARS-CoV virus (SARS).
source https://phys.org/news/2020-12-covid-infection-mutations.html