Data and code availability
The cryo-EM density maps and the structures were deposited into the Electron Microscopy Data Bank (EMDB) and Protein Data Bank (PDB) with the accession numbers 34308 and 8GWB for E-RTC:RNA-nsp9, 34310 and 8GWE for E-RTC:RNA-nsp9:GMPPNP, 34311 and 8GWF for E-RTC:RNA-nsp9:GTP, 34314 and 8GWK for E-RTC:RMP-nsp9:GMPPNP, 34317 and 8GWN for E-RTC:ATMP-nsp9:GMPPNP, 34316 and 8GEM for E-RTC:MMP-nsp9:GMPPNP, 34312 and 8GWG for E-RTC:SMP-nsp9:GMPPNP, 34313 and 8GWI for E-RTC:SMP-nsp9:GTP, 34302 and 8GW1 for E-RTC:UMP-nsp9, 34318 for 8GWO for E-RTC:UMP-nsp9:GMPPNP.