Molecular structure of the papain-like enzyme known as PLPro. This enzyme allows the viruses that cause SARS, MERS, and COVID-19 to infect cells and replicate and suppress the host’s immune function. Now that the enzyme structure is known in detail, new antiviral drugs can be designed. Credit: Jack Henderson, University of Maryland School of Pharmacy

COVID-19 is known to be caused by a virus called SARS-CoV-2, which is similar in structure to two other viruses that have caused recent outbreaks. SARS-CoV, which caused an outbreak of SARS in 2003, and MERS-CoV, the cause of a 2012 outbreak of Middle East Respiratory Syndrome.

In the Journal of Chemical Physics, scientists from the University of Maryland School of Pharmacy report molecular-level investigations of these three viruses, providing a possible pathway to new antiviral drugs to fight all three diseases. At the present time, no effective treatment or drugs exist for any of these coronavirus diseases.

The investigators looked at a viral protein that plays a key role in the ability of the virus to replicate itself once inside the body. This protein also plays a role in defeating the host’s immune system, so it provides a particularly attractive target for potential drug treatments.

The protein, an enzyme known as the papainlike protease, PLPro, is nearly identical in SARS-CoV-2 and SARS-CoV but is slightly different in MERS-CoV. Very recently, the first structural X-ray of this enzyme revealed a shape in the catalytic domain somewhat like a hand with a “thumb,” “palm,” and “fingers.”

Source: https://phys.org/news/2020-09-molecular-viruses-covid-sars-mers.html