Insulation and wiring specificity of BceR-like response regulators and their target promoters in Bacillus subtilis

Fang, Chong; Nagy-Staron, Anna; Grafe, Martin; Heermann, Ralf; Jung, Kirsten; Gebhard, Susanne und Mascher, Thorsten (2017): Insulation and wiring specificity of BceR-like response regulators and their target promoters in Bacillus subtilis. In: Molecular Microbiology, Bd. 104, Nr. 1: S. 16-31

Abstract

BceRS and PsdRS are paralogous two-component systems in Bacillus subtilis controlling the response to antimicrobial peptides. In the presence of extracellular bacitracin and nisin, respectively, the two response regulators (RRs) bind their target promoters, P-bceA or P-psdA, resulting in a strong up-regulation of target gene expression and ultimately antibiotic resistance. Despite high sequence similarity between the RRs BceR and PsdR and their known binding sites, no cross-regulation has been observed between them. We therefore investigated the specificity determinants of PbceA and PpsdA that ensure the insulation of these two paralogous pathways at the RR-promoter interface. In vivo and in vitro analyses demonstrate that the regulatory regions within these two promoters contain three important elements: in addition to the known (main) binding site, we identified a linker region and a secondary binding site that are crucial for functionality. Initial binding to the high-affinity, low-specificity main binding site is a prerequisite for the subsequent highly specific binding of a second RR dimer to the low-affinity secondary binding site. In addition to this hierarchical cooperative binding, discrimination requires a competition of the two RRs for their respective binding site mediated by only slight differences in binding affinities.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Biologie > Department Biologie I
• Fakultätsübergreifende Einrichtungen: Center for Integrated Protein Science Munich (CIPSM)
• Themengebiete: 500 Naturwissenschaften und Mathematik > 570 Biowissenschaften; Biologie ; 500 Naturwissenschaften und Mathematik > 540 Chemie
• ISSN: 0950-382X
• Sprache: Englisch