An ART-fold Rhs toxin from Pluralibacter gergoviae defines Tne5, a novel family of NAD(P) glycohydrolases effectors
Abstract
The type VI secretion system (T6SS) is a widespread bacterial nanomachine that mediates interbacterial competition by delivering toxic effectors into neighboring cells. Among these, enzymes targeting nicotinamide adenine dinucleotide (NAD) cofactors and NAD phosphate (NAD(P)) are particularly potent because they rapidly disrupt redox homeostasis and central metabolism. Several families of T6SS-associated NAD(P)consuming effectors (Tne1-Tne4) have been described. Here, we characterize a T6SS-associated Rearrangement hot spot toxin from Pluralibacter gergoviae. Competition assays show that P. gergoviae kills Escherichia coli in a T6SS-dependent manner. Heterologous production reveals that the Rearrangement hot spot C-terminal extension is toxic in the Escherichia coli cytoplasm and that co-production with the protein encoded downstream neutralizes this activity. AlphaFold3 modeling predicts that the toxin adopts an ADP-ribosyltransferase-like α/β fold with a putative catalytic pocket accommodating NADH. By contrast to T6SS ART toxins described so far, the toxin does not inhibit transcription or translation but instead depletes NAD(P) in vitro and causes intracellular NAD depletion in intoxicated cells. Nuclear magnetic resonance analyses further show that the toxin hydrolyzes NAD + into nicotinamide and ADP-ribose. Phylogenetic analyses and structural modeling show that this effector defines a new ART-related family of NAD(P) glycohydrolases broadly distributed across antagonistic systems, which we propose to name Tne5.
Related
- “Late” effectors from Leptosphaeria maculans as tools for identifying novel sources of resistance in Brassica napus
- Transplant mice with acute viral infection develop functionally distinct antigen-specific PD-1− and PD-1+ CXCR5+CD8+ T-cell effectors
- 902 Reprogrammed regulatory T cells as cytotoxic effectors drive anti-tumor immunity under bispecific T cell engager therapy
- Bacterial effectors targeting the host ubiquitin system
- Bacterial lipid effectors subvert host autophagic flux by inducing lysosomal dysfunction
BibTeX
@article{desjardins2026artfold,
title = {{An ART-fold Rhs toxin from Pluralibacter gergoviae defines Tne5, a novel family of NAD(P) glycohydrolases effectors}},
author = {Jonas B Desjardins and Martin Durrmeyer and Olivier Bornet and Eric Cascales},
journal = {Journal of Biological Chemistry},
year = {2026},
month = jul,
doi = {10.1016/j.jbc.2026.113182},
url = {https://amu.hal.science/hal-05738996v1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - An ART-fold Rhs toxin from Pluralibacter gergoviae defines Tne5, a novel family of NAD(P) glycohydrolases effectors
AU - Jonas B Desjardins
AU - Martin Durrmeyer
AU - Olivier Bornet
AU - Eric Cascales
PY - 2026
DA - 2026/07/01
JO - Journal of Biological Chemistry
DO - 10.1016/j.jbc.2026.113182
UR - https://amu.hal.science/hal-05738996v1
AB - The type VI secretion system (T6SS) is a widespread bacterial nanomachine that mediates interbacterial competition by delivering toxic effectors into neighboring cells. Among these, enzymes targeting nicotinamide adenine dinucleotide (NAD) cofactors and NAD phosphate (NAD(P)) are particularly potent because they rapidly disrupt redox homeostasis and central metabolism. Several families of T6SS-associated NAD(P)consuming effectors (Tne1-Tne4) have been described. Here, we characterize a T6SS-associated Rearrangement hot spot toxin from Pluralibacter gergoviae. Competition assays show that P. gergoviae kills Escherichia coli in a T6SS-dependent manner. Heterologous production reveals that the Rearrangement hot spot C-terminal extension is toxic in the Escherichia coli cytoplasm and that co-production with the protein encoded downstream neutralizes this activity. AlphaFold3 modeling predicts that the toxin adopts an ADP-ribosyltransferase-like α/β fold with a putative catalytic pocket accommodating NADH. By contrast to T6SS ART toxins described so far, the toxin does not inhibit transcription or translation but instead depletes NAD(P) in vitro and causes intracellular NAD depletion in intoxicated cells. Nuclear magnetic resonance analyses further show that the toxin hydrolyzes NAD + into nicotinamide and ADP-ribose. Phylogenetic analyses and structural modeling show that this effector defines a new ART-related family of NAD(P) glycohydrolases broadly distributed across antagonistic systems, which we propose to name Tne5.
SN - 0021-9258
SN - 1083-351X
ER -