title: In Vitro Characterization of the Type I Toxin-Antitoxin System bsrE/SR5 from Bacillus subtilis.
abstract: BsrE/SR5 is a new type I toxin/antitoxin system located on the prophage-like region P6 of the Bacillus subtilis chromosome. The bsrE gene encoding a 30-amino acid hydrophobic toxin and the antitoxin gene sr5 overlap at their 3' ends by 112 bp. Overexpression of bsrE causes cell lysis on agar plates. Here, we present a detailed in vitro analysis of bsrE/SR5. The secondary structures of SR5, bsrE mRNA, and the SR5/bsrE RNA complex were determined. Apparent binding rate constants (kapp) of wild-type and mutated SR5 species with wild-type bsrE mRNA were calculated, and SR5 regions required for efficient inhibition of bsrE mRNA narrowed down. In vivo studies confirmed the in vitro data but indicated that a so far unknown RNA binding protein might exist in B. subtilis that can promote antitoxin/toxin RNA interaction. Using time course experiments, the binding pathway of SR5 and bsrE RNA was elucidated. A comparison with the previously well characterized type I TA system from the B. subtilis chromosome, bsrG/SR4, reveals similarities but also significant differences.
authors.affiliation: From the AG Bakteriengenetik, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, D-07743 Jena, Germany.
authors.forename: Christin
authors.initials: C
authors.lastname: Meißner
authors.affiliation: From the AG Bakteriengenetik, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, D-07743 Jena, Germany.
authors.forename: Natalie
authors.initials: N
authors.lastname: Jahn
authors.affiliation: From the AG Bakteriengenetik, Lehrstuhl für Genetik, Friedrich-Schiller-Universität Jena, D-07743 Jena, Germany Sabine.Brantl@rz.uni-jena.de.
authors.forename: Sabine
authors.initials: S
authors.lastname: Brantl
mesh_terms: D000992:Antitoxins / Q000378:metabolism*; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D009690:Nucleic Acid Conformation; D011485:Protein Binding; D017433:Protein Structure, Secondary; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013997:Time Factors
chemical_list: D000992:Antitoxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D012333:RNA, Messenger
keywords: Bacillus; RNA folding; RNA structure; antisense RNA; gene regulation