Structural and functional diversity of toxin-antitoxin-chaperone systems - PubMed
4 hours ago
- #TAC systems
- #SecB chaperone
- #phage defense
- Toxin-antitoxin-chaperone (TAC) systems consist of a toxin, antitoxin, and SecB-like chaperone (SecBTA), playing roles in phage defense.
- Three major SecB subfamilies were identified: two housekeeping groups and a diverse SecBTA clade linked to eight TAC classes, five of which are newly discovered.
- Structural predictions indicate conserved SecB tetrameric folds and toxin-antitoxin interfaces despite sequence divergence.
- SecB chaperone phylogeny does not align with TA component identity, suggesting modular shuffling in TAC evolution.
- Class 2 ART toxins from Escherichia coli, Bacillus subtilis, and Streptococcus gordonii inhibit protein synthesis.
- All TAC classes can be prophage encoded, indicating phage-driven mobility and rapid diversification.