This study reports the cryo-EM structure of a Type I-A prokaryotic anti-phage defense mechanism, Retron Ec78, and in particular of the PtuA hexameric ATPase putatively bound to the PtuB nuclease. Beyond its known role in abortive infection via tRNA degradation, the authors demonstrate that the PtuAB complex also exhibits DNA-cleaving activity.
- Leyuan Duan
- Lu Chen
- Qingguo Gong