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

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 Pseudom...

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Detalles Bibliográficos
Autores principales: Talavera, Ariel, Tamman, Hedvig, Ainelo, Andres, Konijnenberg, Albert, Hadži, San, Sobott, Frank, Garcia-Pino, Abel, Hõrak, Rita, Loris, Remy
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2019
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6393540/
https://www.ncbi.nlm.nih.gov/pubmed/30814507
http://dx.doi.org/10.1038/s41467-019-08865-z
Descripción
Sumario: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 GraT(2)A(2) 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.