Salmonella antibacterial Rhs polymorphic toxin inhibits translation through ADP-ribosylation of EF-Tu P-loop.
Jurenas, D., Rey, M., Byrne, D., Chamot-Rooke, J., Terradot, L., Cascales, E.(2022) Nucleic Acids Res 50: 13114-13127
- PubMed: 36484105 
- DOI: https://doi.org/10.1093/nar/gkac1162
- Primary Citation of Related Structures:  
7ZHL, 7ZHM - PubMed Abstract: 
Rearrangement hot spot (Rhs) proteins are members of the broad family of polymorphic toxins. Polymorphic toxins are modular proteins composed of an N-terminal region that specifies their mode of secretion into the medium or into the target cell, a central delivery module, and a C-terminal domain that has toxic activity. Here, we structurally and functionally characterize the C-terminal toxic domain of the antibacterial Rhsmain protein, TreTu, which is delivered by the type VI secretion system of Salmonella enterica Typhimurium. We show that this domain adopts an ADP-ribosyltransferase fold and inhibits protein synthesis by transferring an ADP-ribose group from NAD+ to the elongation factor Tu (EF-Tu). This modification is specifically placed on the side chain of the conserved D21 residue located on the P-loop of the EF-Tu G-domain. Finally, we demonstrate that the TriTu immunity protein neutralizes TreTu activity by acting like a lid that closes the catalytic site and traps the NAD+.
Organizational Affiliation: 
Laboratoire d'Ingénierie des Systèmes Macromoléculaires (LISM), Institut de Microbiologie, Bioénergies et Biotechnologie (IM2B), Aix-Marseille Université, CNRS, UMR 7255, 13009 Marseille, France.