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Publication Abstract from PubMed

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 GraT2A2 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.

A dual role in regulation and toxicity for the disordered N-terminus of the toxin GraT.,Talavera A, Tamman H, Ainelo A, Konijnenberg A, Hadzi S, Sobott F, Garcia-Pino A, Horak R, Loris R Nat Commun. 2019 Feb 27;10(1):972. doi: 10.1038/s41467-019-08865-z. PMID:30814507^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.