title: Transcriptional and translational adaptation to aerobic nitrate anabolism in the denitrifierParacoccus denitrificans.
abstract: Transcriptional adaptation to nitrate-dependent anabolism byParacoccus denitrificansPD1222 was studied. A total of 74 genes were induced in cells grown with nitrate as N-source compared with ammonium, includingnasTSABGHCandntrBCgenes. ThenasTandnasSgenes were cotranscribed, althoughnasTwas more strongly induced by nitrate thannasSThenasABGHCgenes constituted a transcriptional unit, which is preceded by a non-coding region containing hairpin structures involved in transcription termination. ThenasTSandnasABGHCtranscripts were detected at similar levels with nitrate or glutamate as N-source, butnasABGHCtranscript was undetectable in ammonium-grown cells. The nitrite reductase NasG subunit was detected by two-dimensional polyacrylamide gel electrophoresis in cytoplasmic fractions from nitrate-grown cells, but it was not observed when either ammonium or glutamate was used as the N-source. ThenasTmutant lacked bothnasABGHCtranscript and nicotinamide adenine dinucleotide (NADH)-dependent nitrate reductase activity. On the contrary, thenasSmutant showed similar levels of thenasABGHCtranscript to the wild-type strain and displayed NasG protein and NADH-nitrate reductase activity with all N-sources tested, except with ammonium. Ammonium repression ofnasABGHCwas dependent on the Ntr system. ThentrBCandntrYXgenes were expressed at low levels regardless of the nitrogen source supporting growth. Mutational analysis of thentrBCYXgenes indicated that whilentrBCgenes are required for nitrate assimilation,ntrYXgenes can only partially restore growth on nitrate in the absence ofntrBCgenes. The existence of a regulation mechanism for nitrate assimilation inP. denitrificans, by which nitrate induction operates at both transcriptional and translational levels, is proposed.
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, Córdoba 14071, Spain.
authors.forename: Victor M
authors.initials: VM
authors.lastname: Luque-Almagro
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, Córdoba 14071, Spain.
authors.forename: Isabel
authors.initials: I
authors.lastname: Manso
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Sullivan
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
authors.forename: Gary
authors.initials: G
authors.lastname: Rowley
authors.affiliation: Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, U.K.
authors.forename: Stuart J
authors.initials: SJ
authors.lastname: Ferguson
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, Córdoba 14071, Spain.
authors.forename: Conrado
authors.initials: C
authors.lastname: Moreno-Vivián
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
authors.forename: David J
authors.initials: DJ
authors.lastname: Richardson
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, U.K.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gates
authors.affiliation: Departamento de Bioquímica y Biología Molecular, Universidad de Córdoba, Edificio Severo Ochoa, 1ª planta, Campus de Rabanales, Córdoba 14071, Spain bb2rorum@uco.es.
authors.forename: M Dolores
authors.initials: MD
authors.lastname: Roldán
mesh_terms: D000222:Adaptation, Physiological; D064751:Ammonium Compounds / Q000378:metabolism; D001426:Bacterial Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D004734:Energy Metabolism; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D018698:Glutamic Acid / Q000378:metabolism; D008954:Models, Biological; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D050895:Nitrate Reductase (NADH) / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D009566:Nitrates / Q000378:metabolism*; D058458:Nitrogen Cycle; D010231:Paracoccus denitrificans / Q000201:enzymology / Q000254:growth & development / Q000502:physiology*; D040901:Proteomics / Q000379:methods; D012329:RNA, Bacterial / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional; D012097:Repressor Proteins / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D015534:Trans-Activators / Q000819:agonists / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D064751:Ammonium Compounds; D001426:Bacterial Proteins; D009566:Nitrates; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012097:Repressor Proteins; D015534:Trans-Activators; D018698:Glutamic Acid; D050895:Nitrate Reductase (NADH)
keywords: Paracoccus; global nitrogen regulator Ntr; nitrate assimilation; nitrate reductase; nitrate/nitrite-sensor protein; nitrogen regulation