ジャーナル: Nat Commun / 年: 2019 タイトル: A dual role in regulation and toxicity for the disordered N-terminus of the toxin GraT. 著者: Ariel Talavera / Hedvig Tamman / Andres Ainelo / Albert Konijnenberg / San Hadži / Frank Sobott / Abel Garcia-Pino / Rita Hõrak / Remy Loris / 要旨: 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 ...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.
A: XRE family transcriptional regulator B: XRE family transcriptional regulator C: DNA (30-MER) D: XRE family transcriptional regulator E: XRE family transcriptional regulator F: DNA (30-MER)