Background: HopU1 ADP-ribosylates GRP7, suppressing plant immunity.
Results: The HopU1 structure has two novel loops required for GRP7 recognition, and HopU1 ribosylates GRP7 at an arginine in position 49 disrupting its function.
Conclusion: HopU1 targets a conserved arginine in GRP7, disabling its ability to bind immunity-related RNA.
Significance: The mechanistic details of how HopU1 recognizes its substrate reveal how HopU1 contributes to pathogenesis
