Respiratory inhibitors activate an Fnr-like regulatory protein in Paracoccus denitrificans: implications for the regulation of the denitrification pathway.
Unlike the uncoupler carbonyl cyanide 3-chlorophenyl-hydrazone, the respiratory inhibitors CN-, N3-, NO2- and rotenone enhanced the formation of nitrate and nitrite reductases in highly aerated cultures of the Paracoccus denitrificans ex-conjugant PD1222 (pRW2A/FF). A maximal effect was observed at concentrations partly blocking electron transport to O2. The level of beta-galactosidase reporting the activity of an Fnr-like regulatory protein showed a similar concentration dependency. It is concluded that oxygen is sensed by Fnr in an indirect way, possibly via the redox state of a cellular component.
Department of Biochemistry, Faculty of Science, Masaryk University, Brno, Czech Republic.
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D000332:Aerobiosis; D000693:Anaerobiosis; D001386:Azides / Q000494:pharmacology; D001426:Bacterial Proteins / Q000378:metabolism*; D003486:Cyanides / Q000494:pharmacology; D004579:Electron Transport / Q000187:drug effects; D029968:Escherichia coli Proteins; D007506:Iron-Sulfur Proteins; D009565:Nitrate Reductases / Q000096:biosynthesis / Q000378:metabolism; D009572:Nitrite Reductases / Q000096:biosynthesis / Q000378:metabolism; D009584:Nitrogen / Q000378:metabolism; D009585:Nitrogen Dioxide / Q000494:pharmacology; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects*; D010105:Oxygenases / Q000037:antagonists & inhibitors / Q000378:metabolism; D010231:Paracoccus denitrificans / Q000737:chemistry* / Q000187:drug effects* / Q000502:physiology; D012402:Rotenone / Q000494:pharmacology; D001616:beta-Galactosidase / Q000096:biosynthesis / Q000378:metabolism
D001386:Azides; D001426:Bacterial Proteins; D003486:Cyanides; D029968:Escherichia coli Proteins; C060704:FNR protein, E coli; D007506:Iron-Sulfur Proteins; D012402:Rotenone; D010105:Oxygenases; D009565:Nitrate Reductases; D009572:Nitrite Reductases; D001616:beta-Galactosidase; D009584:Nitrogen; D009585:Nitrogen Dioxide