An Fe(II)-dependent enzyme. Forms the first step in the acetylacetone degradation pathway of Acinetobacter johnsonii. While acetylacetone is by far the best substrate, heptane-3,5-dione, octane-2,4-dione, 2-acetylcyclohexanone and ethyl acetoacetate can also act as substrates.
An Fe(II)-dependent enzyme. Forms the first step in the acetylacetone degradation pathway of Acinetobacter johnsonii. While acetylacetone is by far the best substrate, heptane-3,5-dione, octane-2,4-dione, 2-acetylcyclohexanone and ethyl acetoacetate can also act as substrates
Please wait a moment until the data is sorted. This message will disappear when the data is sorted.
SYSTEMATIC NAME
IUBMB Comments
acetylacetone:oxygen oxidoreductase
An Fe(II)-dependent enzyme. Forms the first step in the acetylacetone degradation pathway of Acinetobacter johnsonii. While acetylacetone is by far the best substrate, heptane-3,5-dione, octane-2,4-dione, 2-acetylcyclohexanone and ethyl acetoacetate can also act as substrates.
Dke1 also performs the atypical cleavage of the alpha-keto acid, 4-hydroxyphenylpyruvate, to form 4-hydroxybenzaldehyde as product instead of the homogentisate product found for 4-hydroxyphenylpyruvate with 4-hydroxyphenylpyruvate dioxygenase, EC 1.13.11.27, analysis of the bonding of the alpha-keto acid, 4-hydroxyphenylpyruvate, to ferrous Dke1 using anaerobic Dke1, added ferrous ammonium sulfate, and 4-hydroxyphenylpyruvate at pH 7.0, overview
Ni(II)-complex-adducts show regioselective oxidative cleavage of the aliphatic C-C bond using dioxygen via the substrate activation mechanism without changing the oxidation state of nickel(II) as similar to the wild type enzyme
iron(II) complexes [Fe(L)(CH3CN)3](SO3CF3)2 of tris(2-pyridyl)-based ligands exhibit very similar chemical surroundings to the active site of the enzyme and mimic its functions
sulfate, necessary for enzyme activity. About 0.9 mol Fe2+/mol wild-type enzyme, less than 5% Fe2+ in mutants except 0.27 mol/mol H104E-enzyme and 0.45 mol/mol H104N-enzyme
Dke1 contains an atypical, three-histidine-ligated, mononuclear non-heme Fe2+ center, spectroscopic analysis, overview. Stabilizing effect of Glu98 on the 6C geometry of the metal center, priming it for substrate ligation. Also Thr107 stabilizes the Fe(II) cofactor
the Fe(II) coordinating triad is composed of three His residues, geometric and electronic structure of the Fe(II) center, structure and function comparison with other dioxygenases containing a two histidines and a carboxylate coordinating the iron center in a facial triad, overview
active site nonheme monoiron(II) center, facially ligated by three histidine residues, overview. Spectral analysis of Dke1 FeII-alpha-keto acid complexes with 4-hydroxyphneylpyruvate, overview
nonheme Fe(II) cofactor, distinct organization of the hydrophilic triad in the free and substrate-ligated wild-type enzyme. In the free species, the Fe(II) center is coordinated to three histidines and one glutamate, whereas the substrate-ligated, catalytically competent enzyme-substrate complex has an Fe(II) center with three-histidine coordination, with a small fraction of three-histidine, one-glutamate coordination
dependent on, metalloenzyme, 1 iron bound per subunit, required for positioning of the substrate and for rendering of the appropriate electronic environment
an interplay of residues Glu98, His104, Glu11 (from the neighbor subunit), and Arg80 is the most important for the Fe2+ transport in and out of the protein. The Fe2+ ion when expelled from the binding site can be trapped at different locations within the enzyme. The neighborhood of residue Glu11 (form the neighbor subunit) is the second most favorable binding site for the Fe2+ ion after the active site
1 M H2O2 causes complete loss of enzyme activity in less than 10 min, contains no Fe2+ (probably oxidized to Fe3+), partial reconstitution (40%) with 2 mM Fe2+, 20 mM Tris/HCl buffer, pH 7.5, 25°C
Dke1 also performs the atypical cleavage of the alpha-keto acid, 4-hydroxyphenylpyruvate, to form 4-hydroxybenzaldehyde as product instead of the homogentisate product found for 4-hydroxyphenylpyruvate with 4-hydroxyphenylpyruvate dioxygenase, EC 1.13.11.27, analysis of the bonding of the alpha-keto acid, 4-hydroxyphenylpyruvate, to ferrous Dke1 using anaerobic Dke1, added ferrous ammonium sulfate, and 4-hydroxyphenylpyruvate at pH 7.0, overview. active site was modeling, histidine residues are truncated to methyl imidazole for the model, and constraints imposed by the protein backbone are simulated by fixing the relative positions of the beta-carbons of the backbone. The coordination of the active site is completed with either alpha keto (monoanion) or enolate (dianion) bidentate coordinated 4-hydroxyphenylpyruvate ligand or a monoanionic acetylacetone ligand
Dke1 displays an atypical three-histidine metal binding site. Role of the protein structure in the catalysis of beta-diketone cleavage at the threehistidine metal center of diketone cleaving enzyme by computational methods in correlation with kinetic and mutational analyses. Molecular dynamics simulations, using quantum mechanically deduced parameters for the nonheme Fe(II) cofactor. Distinct organization of the hydrophilic triad in the free and substrate-ligated wild-type enzyme. In the free species, the Fe(II) center is coordinated to three histidines and one glutamate, whereas the substrate-ligated, catalytically competent enzyme-substrate complex has an Fe(II) center with three-histidine coordination, with a small fraction of three-histidine, one-glutamate coordination
molecular dynamic simulations with wild-type and mutants E88Q, R80A, Y70A of the Fe2+ free protein, of the enzyme with Fe2+ bound in the active site, without and with applying random force, and of the proteins with the metal ion located at the entrance of the water tunnel
lower thermal stability of beta-sheet secondary structure, half catalytic center activity and remarkably silent difference in apparent substrate binding compared to the wild type enzyme
approximately 1% of the specific activity of wild-type enzyme with substrate pentan-2,4-dione, retains binding affinity for Fe2+ at binding site I, binding seems to be tighter than in wild-type, small effect on other metal ions
no activity in initial rate assays with substrate pentan-2,4-dione, no binding of Fe2+ at binding site I, binding disruption of Cu2+, Mn2+, and Ni2+ compared with wild-type
conversion of substrate in a strictly Fe2+-concentration dependent manner, substrate pentan-2,4-dione, no binding of Fe2+ at binding site I, small effect on other metal ions
an interplay of residues Glu98, His104, Glu11 (from the neighbor subunit), and Arg80 is the most important for the Fe2+ transport in and out of the protein
an interplay of residues Glu98, His104, Glu11 (from the neighbor subunit), and Arg80 is the most important for the Fe2+ transport in and out of the protein
the exchange of 3 histidines in the Fe2+-binding centre shows that these histidines are crucial for for binding Fe2+ and for Fe2+-dependent dioxygenase activity
the exchange of 3 histidines in the Fe2+-binding centre shows that these histidines are crucial for for binding Fe2+ and for Fe2+-dependent dioxygenase activity
purified, concentrated enzyme is dialyzed twice against 2 mM EDTA in 20 mM Tris/HCl (pH 7.5) to strip off iron, incubation in 2 mM metal ion as sulfate salt plus ascorbate to prevent Fe2+ oxidation, unbound metal ions are removed by 3 cycles of gel filtration using nucleic acid purification column
Sepharose Q fast flow column chromatography Superdex 200 gel filtration, Resource Q column chromatography, Nap-5 column gel filtration, and Phenyl Sepharose HP chromatography
biodegradation by the enzyme of the widely used industrial chemical acetylacetone, i.e. 2,4-pentanedione, which has toxic effects, in a membrane bioreactor, determination of operational stability of the enzyme in the reactor at different temperatures, simulations
Straganz, G.D.; Egger, S.; Aquino, G.; DAuria, S.; Nidetzky, B.
Exploring the cupin-type metal-coordinating signature of acetylacetone dioxygenase Dke1 with site-directed mutagenesis: Catalytic reaction profile and Fe2+ binding stability of Glu-69->Gln mutant
Biochemical characterization and mutational analysis of the mononuclear non-haem Fe2+ site in Dke1, a cupin-type dioxygenase from Acinetobacter johnsonii
Kinetic and CD/MCD spectroscopic studies of the atypical, three-His-ligated, non-heme Fe2+ center in diketone dioxygenase: the role of hydrophilic outer shell residues in catalysis
Spectroscopic and computational studies of alpha-keto acid binding to Dke1: understanding the role of the facial triad and the reactivity of beta-diketones
Brkic, H.; Buongiorno, D.; Ramek, M.; Straganz, G.; Tomic, S.
Dke1--structure, dynamics, and function: a theoretical and experimental study elucidating the role of the binding site shape and the hydrogen-bonding network in catalysis