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.
The nir and nor genes, which encode nitrite and nitric oxide reductase, lie close together on the DNA of Paracoccus denitrificans. We here identify an adjacent gene, nnr, which is involved in the expression of nir and nor under anaerobic conditions. The corresponding protein of 224 amino acids is homologous with the family of FNR proteins, although it lacks the N-terminal cysteines. A mutation in the nnr gene had a negative effect on the expression of nitrite and nitric oxide reductase. Synthesis of membrane bound nitrate reductase, of nitrous oxide reductase, and of the cbb3-type cytochrome c oxidase were not affected by mutation of this gene. These results suggest that denitrification in P. denitrificans may be governed by a signal transduction network that is similar to that involved in oxygen regulation of nitrogen metabolism in other organisms.
Van Spanning
R J
RJ
Department of Microbiology, Biological Laboratory, Vrije Universiteit, Amsterdam, The Netherlands.
De Boer
A P
AP
Reijnders
W N
WN
Spiro
S
S
Westerhoff
H V
HV
Stouthamer
A H
AH
Van der Oost
J
J
D000595:Amino Acid Sequence; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D005809:Genes, Regulator; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000378:metabolism*; D009572:Nitrite Reductases / Q000235:genetics; D009573:Nitrites / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000235:genetics; D010231:Paracoccus denitrificans / Q000235:genetics* / Q000378:metabolism; D015183:Restriction Mapping; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics*
D009573:Nitrites; D015534:Trans-Activators; D014157:Transcription Factors; D009569:Nitric Oxide; D010088:Oxidoreductases; D009572:Nitrite Reductases; C034747:nitric-oxide reductase