The enzyme is involved in aerobic benzoate metabolism in Azoarcus evansii. BoxB functions as the oxygenase part of benzoyl-CoA oxygenase in conjunction with BoxA, the reductase component, which upon binding of benzoyl-CoA, transfers two electrons to the ring in the course of monooxygenation. BoxA is a homodimeric 46 kDa iron-sulfur-flavoprotein (FAD), BoxB is a monomeric iron-protein .
epoxidation starts with the binding of the O2 molecule to the diferrous center to generate a diferric peroxide complex, followed by concerted O-O bond cleavage and epoxide formation. Two different pathways have been located, leading to (2S,3R)-epoxy and (2R,3S)-epoxy products. The barrier difference is 2.8 kcal/mol, corresponding to a diastereomeric excess of about 99:1. Further isomerization from epoxide to phenol has quite a high barrier, which cannot compete with the product release step. After product release into solution, fast epoxide-oxepin isomerization and racemization can take place easily, leading to a racemic mixture of (2S,3R) and (2R,3S) products. The deoxygenation of epoxide to regenerate benzoyl-CoA by a diferrous form of the enzyme proceeds via a stepwise mechanism. The C2-O bond cleavage happens first, coupled with one electron transfer from one iron center to the substrate, to form a radical intermediate, which is followed by the second C3-O bond cleavage. The first step is rate-limiting. Reaction mechanism, modeling and simulations, detailed overview
The enzyme is involved in aerobic benzoate metabolism in Azoarcus evansii. BoxB functions as the oxygenase part of benzoyl-CoA oxygenase in conjunction with BoxA, the reductase component, which upon binding of benzoyl-CoA, transfers two electrons to the ring in the course of monooxygenation. BoxA is a homodimeric 46 kDa iron-sulfur-flavoprotein (FAD), BoxB is a monomeric iron-protein [1].
BoxB functions as the oxygenase part of benzoyl-CoA oxygenase in conjunction with BoxA, the reductase component. BoxA functions as the reducing component of benzoyl-CoA oxygenase, which, upon binding of benzoyl-CoA, transfers two electrons to the ring in the course of dioxygenation
BoxB functions as the oxygenase part of benzoyl-CoA oxygenase in conjunction with BoxA, the reductase component. BoxA functions as the reducing component of benzoyl-CoA oxygenase, which, upon binding of benzoyl-CoA, transfers two electrons to the ring in the course of dioxygenation
purified reductase component BoxA catalyses, in the absence of BoxB, the electron transfer from NADPH to free FAD with a rate of 17 mmol/min*mg protein. This activity is very high compared to the benzoyl-CoA conversion rate with purified BoxAB (0.29 mmol/min*mg BoxA). The reductase component BoxA oxidizes NADPH to transfer electrons, mediated by enzyme-bound FAD, to one or two of the [4Fe-4S] centres of the protein. The flow of electrons from NADPH to the artificial electron acceptor, free FAD, is greatly (10-fold) stimulated by binding of benzoyl-CoA to BoxA
benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity
benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity. The enzyme may also catalyze the deoxygenation reaction of epoxide, suggesting a unique bifunctionality among the diiron enzymes
benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity
benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity
benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity. The enzyme may also catalyze the deoxygenation reaction of epoxide, suggesting a unique bifunctionality among the diiron enzymes
benzoyl-CoA epoxidase is a dinuclear iron enzyme that catalyzes the epoxidation reaction of the aromatic ring of benzoyl-CoA with chemo-, regio- and stereo-selectivity
the reductase componment BoxA contains 0.72 mol flavin adenine dinucleotide. BoxA oxidizes NADPH to transfer electrons, mediated by enzyme-bound FAD, to one or two of the [4Fe-4S] centres of the protein. The flow of electrons from NADPH to the artificial electron acceptor, free FAD, is greatly (10-fold) stimulated by binding of benzoyl-CoA to BoxA
the reductase component BoxA oxidizes NADPH to transfer electrons, mediated by enzyme-bound FAD, to one or two of the [4Fe-4S] centres of the protein. The flow of electrons from NADPH to the artificial electron acceptor, free FAD, is greatly (10-fold) stimulated by binding of benzoyl-CoA to BoxA. No oxidation of NADH
BoxA is a homodimeric 46 kDa iron-sulfur-flavoprotein, which acts as reductase. BoxB is a monomeric iron-protein. Subunit BoxB contains 1.6 mol of iron per mol of protein, addition of 1 mM Fe2+ to the assays has no stimulatory or inhibitory effect on the catalytic turnover
the reductase componment BoxA contains 10.4 to 18.4 mol of Fe, and 13.3 to 17.9 mol of acid-labile sulfur per mol of native protein, depending on the method of protein determination
a non-heme diiron enzyme. The two iron ions are bridged by a glutamate (Glu150). The first Fe2+ is ligated by a glutamate (Glu120) and a histidine (His153), while the second Fe2+ is ligated by an aspartate (Asp211), a glutamate (Glu240) and a histidine (His243)
higher salt concentration (500 mM KCl) results in sixfold lower activity suggesting that the interaction of the protein components is affected by high salt concentration
addition of the putative ring cleaving enzyme BoxC leads to a several-fold acceleration of the initial rate and completes conversion of benzoyl-CoA. BoxC might facilitate the binding of BoxA to BoxB and thus lead to the observed rate increase
pH 8, 22°C, addition of the putative ring cleaving enzyme BoxC leads to a several-fold acceleration of the initial rate and completes conversion of benzoyl-CoA. Because of this complex behaviour of the oxygenase system, the apparent Km value for benzoyl-CoA can only be estimated from the time curve of benzoyl-CoA concentration in an assay mixture that contains BoxAB and the putative ring-cleaving enzyme BoxC. This curve shows a half-maximal rate at a benzoyl-CoA concentration of 0.03 mM
benzoyl-CoA substrate forms two hydrogen bonds with Gln116, which in turn is hydrogen-bonded to Glu120. A number of other second-shell residues are also important for the orientation of the benzoyl moiety, including Thr119, Ser123, Phe193, Phe203, and Thr210. Optimized structure of the BoxB active site with the truncated benzoyl-CoA and O2 substrates bound, corresponding to the Michaelis complex, enzyme structure and reaction mechanism mechanics/molecular mechanics calculations and modeling, overview
usage of PDB ID 3PM5 for enzyme structure modeling and simulation, quantum mechanics/molecular mechanics calculations, overview. Four general pathways for oxidizing aromatic rings are determined
usage of PDB ID 3PM5 for enzyme structure modeling and simulation, quantum mechanics/molecular mechanics calculations, overview. Four general pathways for oxidizing aromatic rings are determined
2 * 46000 (BoxA) + 50000 (BoxB), boxA/boxB system, BoxA is a homodimeric 46 kDa iron-sulfur-flavoprotein, which acts as reductase. BoxB is a monomeric iron-protein (50000-60000 Da, gel filtration. 50000 Da, SDS-PAGE)
x + 55000 (benzoyl-CoA oxygenase component B) + x * 46000, (benzoyl-CoA oxygenase component A), BoxB functions as the oxygenase part of benzoyl-CoA oxygenase in conjunction with BoxA, the reductase component. BoxA functions as the reducing component of benzoyl-CoA oxygenase, which, upon binding of benzoyl-CoA, transfers two electrons to the ring in the course of dioxygenation, calculated from sequence
2 * 46000 (BoxA) + 50000 (BoxB), boxA/boxB system, BoxA is a homodimeric 46 kDa iron-sulfur-flavoprotein, which acts as reductase. BoxB is a monomeric iron-protein (50000-60000 Da, gel filtration. 50000 Da, SDS-PAGE)
x + 55000 (benzoyl-CoA oxygenase component B) + x * 46000, (benzoyl-CoA oxygenase component A), BoxB functions as the oxygenase part of benzoyl-CoA oxygenase in conjunction with BoxA, the reductase component. BoxA functions as the reducing component of benzoyl-CoA oxygenase, which, upon binding of benzoyl-CoA, transfers two electrons to the ring in the course of dioxygenation, calculated from sequence
2 * 46000 (BoxA) + 50000 (BoxB), boxA/boxB system, BoxA is a homodimeric 46 kDa iron-sulfur-flavoprotein, which acts as reductase. BoxB is a monomeric iron-protein (50000-60000 Da, gel filtration. 50000 Da, SDS-PAGE)
1.14.13.208 benzoyl-CoA 2,3-epoxidase
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