Illustration of an ExoN (IMAGE) Iowa State University Caption On the left, potential mechanism of action of nucleoside antivirals, exemplified by remdesivir, against SARS-CoV-2 replication and how the virus proofreading ExoN enzyme counteracts the antivirals by eliminating them from the virus RNA. On the right, the atomic structure of the SARS-CoV-2 ExoN enzyme captured in the moment that it recognizes and corrects a mismatch in the virus RNA. The region highlighted by a purple circle is of particular interest because it can serve as the binding site for small molecules that deactivates the ExoN enzyme. Credit Yang Yang Usage Restrictions none License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.