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Structural and functional diversity of toxin-antitoxin-chaperone systems

Nakamoto, Jose A LU orcid ; Odai, Roni LU ; Mets, Toomas LU ; Tenson, Tanel ; Kurata, Tatsuaki LU ; Hauryliuk, Vasili LU orcid and Atkinson, Gemma C LU orcid (2026) In Cell Reports 45(3).
Abstract

Toxin-antitoxin-chaperone (TAC) systems are three-part gene clusters encoding a toxin, antitoxin, and specialized SecB-like chaperone (SecB
TA) with emerging roles in phage defense. To identify and classify SecB homologs and associated TACs across bacteria, we surveyed the full RefSeq database. Phylogenetic and gene neighborhood analyses reveal three major SecB subfamilies: two housekeeping groups and a diverse SecB
TA clade associated with eight TAC classes, five of which were previously unknown. Despite broad sequence divergence, structural predictions show conserved SecB tetrameric folds and toxin-antitoxin interfaces. The SecB chaperone phylogeny is incongruent with the identity of the TA component, suggesting modular... (More)

Toxin-antitoxin-chaperone (TAC) systems are three-part gene clusters encoding a toxin, antitoxin, and specialized SecB-like chaperone (SecB
TA) with emerging roles in phage defense. To identify and classify SecB homologs and associated TACs across bacteria, we surveyed the full RefSeq database. Phylogenetic and gene neighborhood analyses reveal three major SecB subfamilies: two housekeeping groups and a diverse SecB
TA clade associated with eight TAC classes, five of which were previously unknown. Despite broad sequence divergence, structural predictions show conserved SecB tetrameric folds and toxin-antitoxin interfaces. The SecB chaperone phylogeny is incongruent with the identity of the TA component, suggesting modular shuffling during TAC evolution. We demonstrate toxicity of class 2 ART toxins from Escherichia coli, Bacillus subtilis, and Streptococcus gordonii, all of which we show inhibit protein synthesis. All TAC classes can be prophage encoded, indicative of phage-driven mobility and rapid diversification.

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author
; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Cell Reports
volume
45
issue
3
article number
117024
publisher
Cell Press
external identifiers
  • pmid:41779618
ISSN
2211-1247
DOI
10.1016/j.celrep.2026.117024
language
English
LU publication?
yes
additional info
Copyright © 2026 The Author(s). Published by Elsevier Inc. All rights reserved.
id
a2bc7614-c522-448a-8e11-86eb0bd7352a
date added to LUP
2026-03-23 09:21:45
date last changed
2026-03-23 12:01:51
@article{a2bc7614-c522-448a-8e11-86eb0bd7352a,
  abstract     = {{<p>Toxin-antitoxin-chaperone (TAC) systems are three-part gene clusters encoding a toxin, antitoxin, and specialized SecB-like chaperone (SecB<br>
 TA) with emerging roles in phage defense. To identify and classify SecB homologs and associated TACs across bacteria, we surveyed the full RefSeq database. Phylogenetic and gene neighborhood analyses reveal three major SecB subfamilies: two housekeeping groups and a diverse SecB<br>
 TA clade associated with eight TAC classes, five of which were previously unknown. Despite broad sequence divergence, structural predictions show conserved SecB tetrameric folds and toxin-antitoxin interfaces. The SecB chaperone phylogeny is incongruent with the identity of the TA component, suggesting modular shuffling during TAC evolution. We demonstrate toxicity of class 2 ART toxins from Escherichia coli, Bacillus subtilis, and Streptococcus gordonii, all of which we show inhibit protein synthesis. All TAC classes can be prophage encoded, indicative of phage-driven mobility and rapid diversification.<br>
 </p>}},
  author       = {{Nakamoto, Jose A and Odai, Roni and Mets, Toomas and Tenson, Tanel and Kurata, Tatsuaki and Hauryliuk, Vasili and Atkinson, Gemma C}},
  issn         = {{2211-1247}},
  language     = {{eng}},
  month        = {{03}},
  number       = {{3}},
  publisher    = {{Cell Press}},
  series       = {{Cell Reports}},
  title        = {{Structural and functional diversity of toxin-antitoxin-chaperone systems}},
  url          = {{http://dx.doi.org/10.1016/j.celrep.2026.117024}},
  doi          = {{10.1016/j.celrep.2026.117024}},
  volume       = {{45}},
  year         = {{2026}},
}