Explainer: How the COVID-19 virus invades human cells

WASHINGTON — Researchers from China have used cryo-electron microscopy to show how SARS-CoV-2 infects humans. The study published in Science says the virus targets a type of receptor found on human cells in the lungs, heart, kidneys and intestines.

A previous study published in Science found the virus' spike protein has two receptor binding domains, or RBDs, facing downward and another facing upward. These allow the virus to bind with and invade human cells.

According to the new study, the virus targets a human ACE2 receptor that has bonded with an amino acid transporter. This subtype of ACE2 structure has never been discovered before.

The virus uses the spike protein's 'up' RBD to bind with the ACE2 structure, which enables the virus to enter and infect the cell. According to the researchers, their discovery may help in developing a cure or vaccine that prevents infection by targeting ACE2.