An alphacoronavirus polymerase structure reveals conserved co-factor functions.

Coronaviruses are important human and animal pathogens with a history of crossing over from animal reservoirs into humans leading to epidemics or pandemics. Betacoronaviruses, such as SARS-CoV and SARS-CoV-2, have been the focus of research efforts in the field of coronaviruses, leaving other genera (alpha, gamma, and delta) understudied. To broaden our understanding, we studied an alphacoronavirus polymerase complex. We solved the first structure of a non-betacoronavirus replication complex, and in doing so identified previously unknown, and conserved, aspects of polymerase cofactor interactions. Our work displays the importance of studying coronaviruses from all genera and provides important insight into coronavirus replication that can be used for antiviral drug development.