Previous research revealed that coronaviruses invade cells through so-called “spike” proteins, but those proteins take on different shapes in different coronaviruses. Figuring out the shape of the spike protein in SARS-Cov-2 is the key to figuring out how to target the virus, said Jason McLellan, senior author of the study and an associate professor of molecular biosciences at the University of Texas at Austin.

Though the coronavirus uses many different proteins to replicate and invade cells, the spike protein is the major surface protein that it uses to bind to a receptor — another protein that acts like a doorway into a human cell. After the spike protein binds to the human cell receptor, the viral membrane fuses with the human cell membrane, allowing the genome of the virus to enter human cells and begin infection. So “if you can prevent attachment and fusion, you will prevent entry,” McLellan told Live Science. But to target this protein, you need to know what it looks like.