Dataset Information

NosR, a membrane-bound regulatory component necessary for expression of nitrous oxide reductase in denitrifying Pseudomonas stutzeri.

ABSTRACT: The regulatory element NosR was identified within the nos region of the denitrification gene cluster of Pseudomonas stutzeri ZoBell (ATCC 14405) and characterized. It is essential for expression of the N2O reductase encoded by nosZ immediately downstream of nosR. The nosR region was initially identified by Tn5 mutagenesis (W. G. Zumft, K. Döhler, and H. Körner, J. Bacteriol. 163:918-924, 1985). It consists of a single open reading frame of 2,172 nucleotides and has the coding capacity for an 81.9-kDa protein. The codon usage for nosR, with its high G + C content of 62.4 mol% and a preference for G or C at the third position, is characteristic for a Pseudomonas gene. Hydropathy analysis classified NosR as an integral membrane protein with at least seven membrane-spanning segments. No similarity to known bacterial regulator proteins was found in a data bank search. However, the C terminus of NosR shows sequence similarity to the cysteine clusters of several 2[4Fe-4S] bacterial ferrodoxins. A monocistronic mRNA for nosZ which allowed us to monitor NosR function was identified. Complementation of Nos- mutant MK418 (nosR::Tn5) with the nosR gene supplied in trans restored nosZ transcription and expression of a catalytically active N2O reductase. In addition to evidence of the requirement for NosR, indirect evidence for involvement of the transcriptional regulator Fnr is presented.

SUBMITTER: Cuypers H

PROVIDER: S-EPMC206370 | biostudies-other | 1992 Aug

REPOSITORIES: biostudies-other

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NosR, a membrane-bound regulatory component necessary for expression of nitrous oxide reductase in denitrifying Pseudomonas stutzeri.

Cuypers H H Viebrock-Sambale A A Zumft W G WG

Journal of bacteriology 19920801 16

The regulatory element NosR was identified within the nos region of the denitrification gene cluster of Pseudomonas stutzeri ZoBell (ATCC 14405) and characterized. It is essential for expression of the N2O reductase encoded by nosZ immediately downstream of nosR. The nosR region was initially identified by Tn5 mutagenesis (W. G. Zumft, K. Döhler, and H. Körner, J. Bacteriol. 163:918-924, 1985). It consists of a single open reading frame of 2,172 nucleotides and has the coding capacity for an 81. ...[more]

PMID: 1644760

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Project description:BackgroundFirmicutes have the capacity to remove excess nitrate from the environment via either denitrification, dissimilatory nitrate reduction to ammonium or both. The recent renewed interest in their nitrogen metabolism has revealed many interesting features, the most striking being their wide variety of dissimilatory nitrate reduction pathways. In the present study, nitrous oxide production from Bacillus licheniformis, a ubiquitous Gram-positive, spore-forming species with many industrial applications, is investigated.ResultsB. licheniformis has long been considered a denitrifier but physiological experiments on three different strains demonstrated that nitrous oxide is not produced from nitrate in stoichiometric amounts, rather ammonium is the most important end-product, produced during fermentation. Significant strain dependency in end-product ratios, attributed to nitrite and ammonium, and medium dependency in nitrous oxide production were also observed. Genome analyses confirmed the lack of a nitrite reductase to nitric oxide, the key enzyme of denitrification. Based on the gene inventory and building on knowledge from other non-denitrifying nitrous oxide emitters, hypothetical pathways for nitrous oxide production, involving NarG, NirB, qNor and Hmp, are proposed. In addition, all publically available genomes of B. licheniformis demonstrated similar gene inventories, with specific duplications of the nar operon, narK and hmp genes as well as NarG phylogeny supporting the evolutionary separation of previously described distinct BALI1 and BALI2 lineages.ConclusionsUsing physiological and genomic data we have demonstrated that the common soil bacterium B. licheniformis does not denitrify but is capable of fermentative dissimilatory nitrate/nitrite reduction to ammonium (DNRA) with concomitant production of N2O. Considering its ubiquitous nature and non-fastidious growth in the lab, B. licheniformis is a suitable candidate for further exploration of the actual mechanism of N2O production in DNRA bacteria and its relevance in situ.

Dataset Information

NosR, a membrane-bound regulatory component necessary for expression of nitrous oxide reductase in denitrifying Pseudomonas stutzeri.

Publications

NosR, a membrane-bound regulatory component necessary for expression of nitrous oxide reductase in denitrifying Pseudomonas stutzeri.

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