A dual role in regulation and toxicity for the disordered N-terminus of the toxin GraT.

TitleA dual role in regulation and toxicity for the disordered N-terminus of the toxin GraT.
Publication TypeJournal Article
Year of Publication2019
AuthorsTalavera, A., H. Tamman, A. Ainelo, A. Konijnenberg, S. Hadži, F. Sobott, A. Garcia-Pino, R. Hõrak, and R. Loris
JournalNat Commun
Date Published2019 02 27
KeywordsAntitoxins, Bacterial Proteins, Bacterial Toxins, DNA, Bacterial, Genes, Bacterial, Intrinsically Disordered Proteins, Models, Molecular, Nucleic Acid Conformation, Operon, Promoter Regions, Genetic, Protein Binding, Protein Folding, Protein Structure, Quaternary, Pseudomonas putida, Static Electricity, Toxin-Antitoxin Systems

Bacterial toxin-antitoxin (TA) modules are tightly regulated to maintain growth in favorable conditions or growth arrest during stress. A typical regulatory strategy involves the antitoxin binding and repressing its own promoter while the toxin often acts as a co-repressor. Here we show that Pseudomonas putida graTA-encoded antitoxin GraA and toxin GraT differ from other TA proteins in the sense that not the antitoxin but the toxin possesses a flexible region. GraA auto-represses the graTA promoter: two GraA dimers bind cooperatively at opposite sides of the operator sequence. Contrary to other TA modules, GraT is a de-repressor of the graTA promoter as its N-terminal disordered segment prevents the binding of the GraTA complex to the operator. Removal of this region restores operator binding and abrogates Gr aT toxicity. GraTA represents a TA module where a flexible region in the toxin rather than in the antitoxin controls operon expression and toxin activity.

Alternate JournalNat Commun
PubMed ID30814507
PubMed Central IDPMC6393540
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