Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.7.1.4 (nitrite reductase)
1,847 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The genes for nitric oxide reductase (norCB) from Pseudomonas aeruginosa were identified and sequenced. They are located about 2 kb upstream of nirS, the structural gene for nitrite reductase. norC and norB encode cytochrome c (16 kDa) and cytochrome b (52 kDa) subunits of the enzyme, respectively. norCB is immediately followed by an open reading frame encoding a protein of 612 residues.
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PMID:The structural genes for nitric oxide reductase from Pseudomonas aeruginosa. 771 Oct 73

By using the gene encoding the C-terminal part of the cd1-type nitrite reductase of Pseudomonas stutzeri JM300 as a heterologous probe, the corresponding gene from Paracoccus denitrificans was isolated. This gene, nirS, codes for a mature protein of 63144 Da having high homology with cd1-type nitrite reductases from other bacteria. Directly downstream from nirS, three other nir genes were found in the order nirECF. The organization of the nir gene cluster in Pa. denitrificans is different from the organization of nir clusters in some Pseudomonads. nirE has high homology with a S-adenosyl-L-methionine:uroporphyrinogen III methyltransferase (uro'gen III methylase). This methylase is most likely involved in the heme d1 biosynthesis in Pa. denitrificans. The third gene, nirC, codes for a small cytochrome c of 9.3 kDa having high homology with cytochrome c55X of Ps. stutzeri ZoBell. The 4th gene, nirF, has no homology with other genes in the sequence databases and has no relevant motifs. Inactivation of either of these 4 genes resulted in the loss of nitrite and nitric oxide reductase activities but not of nitrous oxide reductase activity. nirS mutants lack the cd1-type nitrite reductase while nirE, nirC and nirF mutants produce a small amount of cd1-type nitrite reductase, inactive due to the absence of heme d1. Upstream from the nirS gene the start of a gene was identified which has limited homology with nosR, a putative regulatory gene involved in nitrous oxide reduction. A potential FNR box was identified between this gene and nirS.
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PMID:Isolation, sequencing and mutational analysis of a gene cluster involved in nitrite reduction in Paracoccus denitrificans. 774 27

The Pseudomonas aeruginosa gene anr, which encodes a structural and functional analog of the anaerobic regulator Fnr in Escherichia coli, was mapped to the SpeI fragment R, which is at about 59 min on the genomic map of P. aeruginosa PAO1. Wild-type P. aeruginosa PAO1 grew under anaerobic conditions with nitrate, nitrite, and nitrous oxide as alternative electron acceptors. An anr deletion mutant, PAO6261, was constructed. It was unable to grow with these alternative electron acceptors; however, its ability to denitrify was restored upon the introduction of the wild-type anr gene. In addition, the activities of two enzymes in the denitrification pathway, nitrite reductase and nitric oxide reductase, were not detectable under oxygen-limiting conditions in strain PAO6261 but were restored when complemented with the anr+ gene. These results indicate that the anr gene product plays a key role in anaerobically activating the entire denitrification pathway.
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PMID:Anaerobic activation of the entire denitrification pathway in Pseudomonas aeruginosa requires Anr, an analog of Fnr. 776 75

We examined the denitrification system of the fungus Cylindrocapon tonkinense and found several properties distinct from those of the denitrification system of Fusarium oxysporum. C. tonkinense could form N2O from nitrite under restricted aeration but could not reduce nitrate by dissimilatory metabolism. Nitrite-dependent N2O formation and/or cell growth during the anaerobic culture was not affected by further addition of ammonium ions but was suppressed by respiration inhibitors such as rotenone or antimycin, suggesting that denitrification plays a physiological role in respiration. Dissimilatory nitrite reductase and nitric oxide reductase (Nor) activities could not be detected in cell extracts of the denitrifying cells. The Nor activity was purified and found to depend upon two isoenzymes of Cytochrome P-450nor (P-450nor), which were designated P-450nor1 and P-450nor2. These isozymes differed in the N-terminal amino acid sequence, isoelectric point, specificity to the reduced pyridine nucleotide (NADH or NADPH), and the reactivity to the antibody to P-450nor of F. oxysporum. the difference between the specificities to NADH and NADPH suggests that P-450nor1 and P-450nor2 play different roles in anaerobic energy acquisition.
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PMID:Denitrification by the fungus Cylindrocarpon tonkinense: anaerobic cell growth and two isozyme forms of cytochrome P-450nor. 779 22

Nitrite reductase from Pseudomonas aeruginosa (EC 1.9.3.2), a redox enzyme synthesized by the bacterium grown in the presence of nitrate, is a soluble dimer of two identical subunits of 60 kDa, each containing one c and one d1 haem as prosthetic groups. A new crystal from of the Ps. aeruginosa nitrite reductase in the oxidized state, suitable for X-ray structure determination, has been obtained by vapour diffusion at 20 degrees C, in the presence of 10% polyethylene glycol 4000, 50 mM Tris-HCl (pH 8.7), 400 mM NaCl and at a protein concentration of 14 mg/ml. The crystals are dark green elongated tetragonal prisms of dimensions 1.5 mm x 0.2 mm x 0.2 mm for the largest ones. These crystals are tetragonal with space group P4(1(3))2(1)2 and cell dimensions a = b = 128.2 A, c = 172.6 A. They diffract at least up to 2.8 A. Assuming a dimer in the asymmetric unit, the VM value is 2.95 A3/Da (58% of solvent).
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PMID:Crystallization and preliminary X-ray analysis of a new crystal form of nitrite reductase from Pseudomonas aeruginosa. 793 60

A chromate resistant mutant of Enterobacter aerogenes manifested its chromate resistance only under aerobic conditions. Both parent and mutant showed substantial levels of anaerobic chromate reductase activity when grown on glycerol plus fumarate. The chromate reductase was further induced by growth in the presence of nitrite but was repressed by nitrate. The chromate reductase activity paralleled that of the formate-linked nitrite reductase. There was no significant difference in chromate reductase levels between the parent and its chromate resistant mutant, indicating that this enzyme activity is not, in fact responsible for chromate resistance as was suggested previously by others.
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PMID:Chromate reductase activity of Enterobacter aerogenes is induced by nitrite. 798 66

Ammonia-forming cytochrome c nitrite reductase from Sulfurospirillum deleyianum contains four covalently bound heme c groups/55 kDa subunit as determined by atomic absorption spectroscopy and the pyridine Fe(II)-hemochrome technique. Nitrite reductase was isolated from the membrane fraction as a monomer (M(r) 55 +/- 2 kDa) and as a heterooligomeric complex. Both the monomeric and the complex form of the enzyme exhibited a high specific activity, with up to 1050 mumol NO2-min-1 mg-1. The complex was built from four 55 kDa units and contained a 22 kDa c-type cytochrome which was absent in the monomeric form. EPR spectra of the complex displayed a prominent feature at g 4.83 (baseline crossing). This resonance, which was not observed in the spectra of the monomeric nitrite reductase, was assigned to the 22 kDa c-type cytochrome subunit. Identical results were obtained for the enzyme from Wolinella succinogenes which had been reinvestigated for comparison.
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PMID:Ammonia-forming cytochrome c nitrite reductase from Sulfurospirillum deleyianum is a tetraheme protein: new aspects of the molecular composition and spectroscopic properties. 799 30

The structural gene of the ferredoxin:sulphite reductase (EC 1.8.7.1) from the cyanobacterium Synechococcus PCC7942 (formerly 'Anacystis nidulans') was cloned and sequenced. The gene termed 'sir' was detected by heterologous Southern hybridisation with the structural gene cysI from Escherichia coli encoding the iron-sulphur haemoprotein of the NADPH:sulphite reductase. The open reading frame is comprised of 1875 bp encoding for a polypeptide of M(r) 70.028. The deduced amino acid sequence is 35.6% identical with the enterobacterial iron-sulphur haemoprotein. This putative fd-dependent sulphite reductase is only distantly related to the fd-dependent nitrite reductase (binary matching coefficient SAB: 0.23) or with the NADPH-sulphite reductase (SAB: 0.32). Highly conserved residues are found within the two Cys clusters forming the reactive Fe4S4-sirohaem centre of the enzyme. Expression of the sir gene using a fusion vector gave a single gene product which is immunologically related with the fd-sulphite reductase from the wild-type bacterium.
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PMID:The ferredoxin:sulphite reductase gene from Synechococcus PCC7942. 834 57

The structural gene, nirK, for the respiratory Cu-containing nitrite reductase from denitrifying Pseudomonas aureofaciens was isolated and sequenced. It encodes a polypeptide of 363 amino acids including a signal peptide of 24 amino acids for protein export. The sequence showed 63.8% positional identity with the amino acid sequence of "Achromobacter cycloclastes" nitrite reductase. Ligands for the blue, type I Cu-binding site and for a putative type-II site were identified. The nirK gene was transferred to the mutant MK202 of P. stutzeri which lacks cytochrome cd1 nitrite reductase due to a transposon Tn5 insertion in its structural gene, nirS. The heterologous enzyme was active in vitro and in vivo in this background and restored the mutationally interrupted denitrification pathway. Transfer of nirK to Escherichia coli resulted in an active nitrite reductase in vitro. Expression of the nirS gene from P. stutzeri in P. aureofaciens and E. coli led to nonfunctional gene products. Nitrite reductase activity of cell extract from either bacterium could be reconstituted by addition of heme d1, indicating that both heterologous hosts synthesized a cytochrome cd1 without the d1-group.
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PMID:Copper-containing nitrite reductase from Pseudomonas aureofaciens is functional in a mutationally cytochrome cd1-free background (NirS-) of Pseudomonas stutzeri. 835 48

Eleven green individuals were isolated when 95000 M2 plants of barley (Hordeum vulgare L.), mutagenised with azide in the M1, were screened for nitrite accumulation in their leaves after nitrate treatment in the light. The selected plants were maintained in aerated liquid culture solution containing glutamine as sole nitrogen source. Not all plants survived to flowering and some others that did were not fertile. One of the selected plants, STA3999, from the cultivar Tweed could be crossed to the wild-type cultivar and analysis of the F2 progeny showed that leaf nitrite accumulation was due to a recessive mutation in a single nuclear gene, which has been designated Nir1. The homozygous nir1 mutant could be maintained to flowering in liquid culture with either glutamine or ammonium as sole nitrogen source, but died within 14 days after transfer to compost. The nitrite reductase cross-reacting material seen in nitrate-treated wild-type plants could not be detected in either the leaf or the root of the homozygous nir1 mutant. Nitrite reductase activity, measured with dithionite-reduced methyl viologen as electron donor, of the nitrate-treated homozygous nir1 mutant was much reduced but NADH-nitrate reductase activity was elevated compared to wild-type plants. We conclude that the Nir1 locus determines the formation of nitrite reductase apoprotein in both the leaf and root of barley and speculate that it represents either the nitrite reductase apoprotein gene locus or, less likely, a regulatory locus whose product is required for the synthesis of nitrite reductase, but not nitrate reductase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:nir1, a conditional-lethal mutation in barley causing a defect in nitrite reduction. 843 74


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