Zur Struktur und Funktion regulatorischer Elemente des cbb-Regulons in Ralstonia eutropha

摘要: For autotrophic CO2 assimilation Ralstonia eutropha H16 requires the enzymes of Calvin cycle. The genetic control involved in adjustment carbon metabolism between and heterotrophic conditions primarily affects transcription cbb operons, whose expression is mainly controlled by transcriptional activator CbbR. Within scope this thesis, some already identified regulatory components system from R. were functionally characterized detail additional regulators/modulators found which are potentially operons concert with Site-directed mutagenesis activity measurements used to verify operon promoter PcbbL as a typical σ70-dependent constitutive low level regulator gene PcbbR was detected. Studies mutants CbbR-free background corresponding cbbR deletion mutant have shown, that general regulation pattern systems maintained principle, but on level. In context, DNA-binding studies previously performed vitro suggest existence at least one regulation. Gel mobility shift assays region resulted detection two proteins, P1 P2, and, like CbbR, both specificly bind region. Subsequently P2 an ortholog PhcA solanacearum, acting global organism. Parallel examinations revertant negative deleti spontaneous mutation phcA suppressed deletion. contrast these results wild-type possesses no obvious function it seems play important role for survival under stress conditions. second potential regulator, P1, enriched apparent homogeneity. binding directly upstream Cbbr competition experiments. Binding subfragments indicate modulatory functions protein activation PcbbL. Simultaneous within operator/promoter verified, whereby led significantly decreased induced DNA bending. This ability plays efficient operons. To examine functionality signalmetabolite phosphoenolpyruvate (PEP) E. coli performed. It shown PEP caused repression increased affinity operator presence metabolite. These combined former intracellular PEP-level represents variable central connected system. essential does not seem be unilateral activator, its more integrator processing different signals needed effective