Variable Macro X Domain of SARS-CoV-2 Retains the Ability to Bind ADP-ribose

The virus that causes COVID-19, SARS-CoV-2, has a large RNA genome that en-codes numerous proteins that might be targets for antiviral drugs. Some of these proteins, such as the RNA-dependent RNA polymers, helicase and main protease, are well conserved between SARS-CoV-2 and the original SARS virus, but several others are not. This study examines one of the most novel proteins encoded by SARS-CoV-2, a macrodomain of nonstructural protein 3 (nsp3). Although 26% of the amino acids in this SARS-CoV-2 macrodo-main differ from those seen in other coronaviruses, the protein retains the ability to bind ADP-ribose, which is an important characteristic of beta corona-viruses, and potential therapeutic target.