Any feedback?
Please rate this page
(literature.php)
(0/150)

BRENDA support

Literature summary for 1.7.2.2 extracted from

  • Clarke, T.A.; Kemp, G.L.; Van Wonderen, J.H.; Doyle, R.M.; Cole, J.A.; Tovell, N.; Cheesman, M.R.; Butt, J.N.; Richardson, D.J.; Hemmings, A.M.
    Role of a conserved glutamine residue in tuning the catalytic activity of Escherichia coli cytochrome c nitrite reductase (2008), Biochemistry, 47, 3789-3799.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
gene nrfA, expression of wild-type and mutant enzymes in Escherichia coli strain JCB4083a Escherichia coli

Crystallization (Commentary)

Crystallization (Comment) Organism
purified recombinant wild-type and mutant Q263E, 10 mg/ml protein, under aerobic conditions by the vapor diffusion hanging drop method using 20% v/v PEG 10000 in 100 mM Na-HEPES, pH 7.5, 20% ethylene glycol as cryoprotectant, X-ray diffraction structure determination and analysis at 1.74 A and 2.04 A resolution, respectively, molecular replacement Escherichia coli

Protein Variants

Protein Variants Comment Organism
Q263E site-directed mutagenesis, the mutation leads to introduction of a negative charge into the vicinity of the active site heme, and the mutant shows reduced activity compared to the wild-type enzyme. The high spin state of the active site to be preserved, indicating that a water/hydroxide molecule is still coordinated to the heme in the resting state of the enzyme Escherichia coli

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
additional information kinetics Escherichia coli
0.033
-
nitrite pH 7.0, 25°C, wild-type enzyme with methyl viologen as reductant Escherichia coli
0.413
-
nitrite pH 7.0, 25°C, mutant Q263E with methyl viologen as reductant Escherichia coli

Metals/Ions

Metals/Ions Comment Organism Structure
Ca2+ the NrfA active site consists of a hexacoordinate high-spin heme with a lysine ligand on the proximal side and water/hydroxide or substrate on the distal side. There are four further highly conserved active site residues including a Q263 positioned near the heme iron for which the side chain, unusually, coordinates a conserved, essential calcium ion, overview. An important function of the unusual Q263-calcium ion pair is to increase substrate affinity through its role in supporting a network of hydrogen bonded water molecules stabilizing the active site heme distal ligand Escherichia coli
Fe3+ active site heme Fe(III) iron, the NrfA active site consists of a hexacoordinate high-spin heme with a lysine ligand on the proximal side and water/hydroxide or substrate on the distal side. There are four further highly conserved active site residues including a Q263 positioned near the heme iron for which the side chain, unusually, coordinates a conserved, essential calcium ion, overview Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
nitrite + ferrocytochrome c + H+ Escherichia coli
-
NH3 + H2O + ferricytochrome c
-
?

Organism

Organism UniProt Comment Textmining
Escherichia coli P0ABK9 gene nrfA
-

Purification (Commentary)

Purification (Comment) Organism
recombinant wild-type and mutant enzymes from Escherichia coli strain JCB4083a by ammonium sulfate fractionation and anion exchange chromatography Escherichia coli

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information the NrfA active site consists of a hexacoordinate high-spin heme with a lysine ligand on the proximal side and water/hydroxide or substrate on the distal side. There are four further highly conserved active site residues including a Q263 positioned near the heme iron for which the side chain, unusually, coordinates a conserved, essential calcium ion, overview. Important function of the Q263-calcium ion pair increasing substrate affinity through its role in supporting a network of hydrogen bonded water molecules stabilizing the active site heme distal ligand, active site structures of native and Q263 mutant NrfA enzymes, overview Escherichia coli ?
-
?
nitrite + ferrocytochrome c + H+
-
Escherichia coli NH3 + H2O + ferricytochrome c
-
?
nitrite + reduced methyl viologen
-
Escherichia coli NH3 + H2O + oxidized methyl viologen
-
?

Synonyms

Synonyms Comment Organism
cytochrome c nitrite reductase
-
Escherichia coli
NrfA
-
Escherichia coli

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
25
-
assay at Escherichia coli

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7
-
assay at Escherichia coli

Cofactor

Cofactor Comment Organism Structure
heme
-
Escherichia coli