Once SARS-CoV-2 invades a healthy human cell, the virus's own genetic material commandeers the infected cell's machinery, forcing it to make new copies of the virus. A vital step in this viral life cycle involves cutting a very long 'polyprotein' into its constituent viral proteins. SARS-CoV-2 has two molecular machines called protease enzymes that act as 'molecular scissors'. One of these, called the main protease, or 'Mpro' for short, has the vital role of chopping up the polyprotein, cutting it at 11 different places.

Using a wide array of computational molecular modelling techniques including interactive molecular dynamics in virtual reality, quantum mechanics, peptide design and protein-ligand interaction analysis, the scientists were able to build an atomic level picture of the structure, dynamics and interactions of Mpro.

From these models, the team were able to find how the viral Mpro 'molecular scissors' work. They then designed new peptides, which are short pieces of protein, as inhibitors, to bind tightly to Mpro and prevent it from working, stopping the virus dead in its tracks. 

Read the full University of Bristol press release.