Nitrite and nitric oxide reduction in <i>Paracoccus denitrificans</i> is under the control of NNR, a regulatory protein that belongs to the FNR family of transcriptional activators

Spanning, Rob J.M. van; Boer, A. P. N. De; Reijnders, W. N. M.; Spiro, Stephen; Westerhoff, Hans V.; Stouthamer, A. H.; Oost, John van der

doi:10.1016/0014-5793(95)00091-m

Cited by 87 publications

(82 citation statements)

References 25 publications

(30 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…3. NNR from Paracoccus denitrificans which was recently found to be encoded in the vicinity of the nir and nor genes [19] showed the highest identity (33.3%).…”

Section: Cloning and Sequencing Of The Downstream Region Of The Normentioning

confidence: 99%

Expression of the nir and nor genes for denitrification of Pseudomonas aeruginosa requires a novel CRP/FNR‐related transcriptional regulator, DNR, in addition to ANR

1995

View full text Add to dashboard Cite

A gene, designated dnr, was identified in the vicinity of the structural genes for nitrite reductase (nirS) and nitric oxide reductase (norCB), and the gene for activation of the reductases (nirQ) from Pseudomonas aeruginosa. It encodes a protein of 227 amino acids homologous with the CRPIFNR-family transcriptional regulators. Promoter activities for nirS, nirQ and norCB were considerably reduced in the dnr mutant as well as in the mutant of anr, the other fnr-like regulatory gene from P. aeruginosa. This is the first finding that two CRP/FNR-related regulators are involved in denitrification in one strain.

show abstract

“…3. NNR from Paracoccus denitrificans which was recently found to be encoded in the vicinity of the nir and nor genes [19] showed the highest identity (33.3%).…”

Section: Cloning and Sequencing Of The Downstream Region Of The Normentioning

confidence: 99%

Expression of the nir and nor genes for denitrification of Pseudomonas aeruginosa requires a novel CRP/FNR‐related transcriptional regulator, DNR, in addition to ANR

1995

View full text Add to dashboard Cite

show abstract

“…In Paracoccus denitrificans, the nor operon apparently consists of six genes, which include homologs of the three genes in the P. aeruginosa operon (8). Regulation of nor expression appears to be under the control of the nnrR product in P. denitrificans and Rhodobacter sphaeroides 2.4.3 and an apparent functional homolog of NnrR in P. aeruginosa (2,35,37). NnrR, which is a member of the Fnr/Crp family of transcriptional regulators, regulates both Nor and NO 2 Ϫ reductase (Nir) expression but does not appear to be involved in regulation of other aspects of denitrification.…”

mentioning

confidence: 99%

“…The last two genes are apparently required for expression of both Nir and Nor and have been designated nnrT and nnrU, respectively. The nnr designation was developed by Van Spanning to indicate genes whose products appear to be involved in expression of Nir and Nor (37). nnrT and nnrU can be expressed from an internal promoter, since insertional inactivation within the first four genes does not cause phenotypic changes consistent with loss of expression of the two downstream genes.…”

mentioning

confidence: 99%

Characterization of the nitric oxide reductase-encoding region in Rhodobacter sphaeroides 2.4.3

et al. 1997

View full text Add to dashboard Cite

A gene cluster which includes genes required for the expression of nitric oxide reductase in Rhodobacter sphaeroides 2.4.3 has been isolated and characterized. Sequence analysis indicates that the two proximal genes in the cluster are the Nor structural genes. These two genes and four distal genes apparently constitute an operon. Mutational analysis indicates that the two structural genes, norC and norB, and the genes immediately downstream, norQ and norD, are required for expression of an active Nor complex. The remaining two genes, nnrT and nnrU, are required for expression of both Nir and Nor. The products of norCBQD have significant identity with products from other denitrifiers, whereas the predicted nnrT and nnrU gene products have no similarity with products corresponding to other sequences in the database. Mutational analysis and functional complementation studies indicate that the nnrT and nnrU genes can be expressed from an internal promoter. Deletion analysis of the regulatory region upstream of norC indicated that a sequence motif which has identity to a motif in the gene encoding nitrite reductase in strain 2.4.3 is critical for nor operon expression. Regulatory studies demonstrated that the first four genes, norCBQD, are expressed only when the oxygen concentration is low and nitrate is present but that the two distal genes, nnrTU, are expressed constitutively.Denitrification is the reduction of nitrate (NO 3 Ϫ ) to gaseous intermediates, principally nitrogen gas. Nitric oxide (NO), an obligatory intermediate during denitrification, is generated from the one-electron reduction of nitrite (NO 2 Ϫ ) (41). NO reduction is coupled to energy generation (18,29). NO is also a well-known cytotoxic compound, so its production during denitrification has the potential of causing significant cell damage. To mitigate the toxicity of NO, its steady-state concentration during denitrification is maintained at low-nanomolar levels (11). The protein responsible for NO reduction, NO reductase (Nor), catalyzes the reaction 2NO ϩ 2H ϩ 3N 2 O ϩ H 2 O. Nitrous oxide (N 2 O) is an inert, nontoxic intermediate that is frequently the terminal product of denitrification (42). Nor has been purified and shown to be a heterodimeric membrane protein (9,14,16). Metal analysis has shown that it contains only iron in stoichiometric amounts. Recently, the Nor structural genes have been characterized, and sequence analysis revealed that Nor was related to the cytochrome c oxidase superfamily (36). In particular, Nor is most closely related to the heme b-containing oxidases, which are expressed under conditions of low oxygen concentration. It has been suggested that Nor was the original member of this family and that the other members arose by modifying the Nor structure (26).The genetic organization of the region of the chromosome encoding the nor structural genes varies among denitrifiers. In Pseudomonas stutzeri, the two structural genes form a distinct transcriptional unit (43). In Pseudomonas aeruginosa, the two structural genes ...

show abstract

“…In addition, this demonstrates that Fnr and NnrR, both of which have been implicated as being involved in regulating denitrification in other bacteria (van Spanning et al, 1997 ;Ye et al, 1995), have distinctly different DNA targets in R. sphaeroides. In the related denitrifier Paracoccus denitrificans, binding-site preferences for Fnr and NnrR are difficult to discern from an analysis of the regulatory regions of genes that are expressed anaerobically (van Spanning et al, 1997). This has led to the suggestion that binding discrimination is not only sequence dependent but also occurs through other mechanisms.…”

Section: Discussionmentioning

confidence: 98%

“…One aspect of the regulation of denitrification that has become apparent is that the genes encoding products required for the reduction of nitrite and NO are regulated independently of the other reductases. The concerted regulation of these processes is carried out by a member of the Fnr\CRP family of transcriptional regulators (Arai et al, 1995 ;Tosques et al, 1996 ;van Spanning et al, 1995 ;Vollack & Zumft, 2001). …”

Section: Introductionmentioning

confidence: 99%

Characterization of a member of the NnrR regulon in Rhodobacter sphaeroides 2.4.3 encoding a haem–copper protein The GenBank accession number for nnrS is U62403.

et al. 2002

View full text Add to dashboard Cite

Upstream of the nor and nnrR cluster in Rhodobacter sphaeroides 2.4.3 is a previously uncharacterized gene that has been designated nnrS. nnrS is only expressed when 2.4.3 is grown under denitrifying conditions. Expression of nnrS is dependent on the transcriptional regulator NnrR, which also regulates expression of genes required for the reduction of nitrite to nitrous oxide, including nirK and nor. Deletion analysis indicated the sequence 5'-TTGCG(N 4 )CACAA-3', which is similar to sequences found in nirK and nor, is required for nnrS expression. Mutation of this sequence to the consensus Fnr-binding sequence by changing two bases in each half site caused nnrS expression to become nitrate independent. Inactivation of nnrS did not affect nitric oxide metabolism, nor did it affect expression of any of the genes involved in nitric oxide metabolism. However, taxis towards nitrate and nitrite was affected by nnrS inactivation. Purification of a histidine-tagged NnrS demonstrated that NnrS is a haem-and copper-containing membrane protein.Genes encoding putative orthologues of NnrS are sometimes but not always found in bacteria encoding nitrite and/or nitric oxide reductase.

show abstract

Nitrite and nitric oxide reduction in Paracoccus denitrificans is under the control of NNR, a regulatory protein that belongs to the FNR family of transcriptional activators

Cited by 87 publications

References 25 publications

Expression of the nir and nor genes for denitrification of Pseudomonas aeruginosa requires a novel CRP/FNR‐related transcriptional regulator, DNR, in addition to ANR

Expression of the nir and nor genes for denitrification of Pseudomonas aeruginosa requires a novel CRP/FNR‐related transcriptional regulator, DNR, in addition to ANR

Characterization of the nitric oxide reductase-encoding region in Rhodobacter sphaeroides 2.4.3

Characterization of a member of the NnrR regulon in Rhodobacter sphaeroides 2.4.3 encoding a haem–copper protein The GenBank accession number for nnrS is U62403.

Contact Info

Product

Resources

About