Suitability of the hydrocarbon-hydroxylating molybdenum-enzyme ethylbenzene dehydrogenase for industrial chiral alcohol production

Tataruch, Mateusz; Heider, Johann; Bryjak, Jolanta; Nowak, Paweł; Knack, Daniel H.; Czerniak, A.; Liesienė, Jolanta; Szaleniec, Maciej

doi:10.1016/j.jbiotec.2014.06.021

Cited by 15 publications

(11 citation statements)

References 35 publications

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“…Moreover, the high redox potential fits very well to previous biochemical data of ethylbenzene dehydrogenase, showing that ethylbenzene oxidation is only possible with artificial electron acceptors with high redox potentials (e.g. ferricenium, Fe(CN) 6 3− ) [4,42] or with cytochrome c [43], and to a direct electrochemical analysis of EbDH [44]. Furthermore, the heme b cofactor is located close to the surface of the protein and is supposed to act as electron donor to an external electron acceptor of similarly high potential [18].…”

Section: Heme B Cofactorsupporting

confidence: 84%

Characterisation of the redox centers of ethylbenzene dehydrogenase

et al. 2021

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Ethylbenzene dehydrogenase (EbDH), the initial enzyme of anaerobic ethylbenzene degradation from the beta-proteobacterium Aromatoleumaromaticum, is a soluble periplasmic molybdenum enzyme consisting of three subunits. It contains a Mo-bis-molybdopterin guanine dinucleotide (Mo-bis-MGD) cofactor and an 4Fe–4S cluster (FS0) in the α-subunit, three 4Fe–4S clusters (FS1 to FS3) and a 3Fe–4S cluster (FS4) in the β-subunit and a heme b cofactor in the γ-subunit. Ethylbenzene is hydroxylated by a water molecule in an oxygen-independent manner at the Mo-bis-MGD cofactor, which is reduced from the MoVI to the MoIV state in two subsequent one-electron steps. The electrons are then transferred via the Fe–S clusters to the heme b cofactor. In this report, we determine the midpoint redox potentials of the Mo-bis-MGD cofactor and FS1–FS4 by EPR spectroscopy, and that of the heme b cofactor by electrochemically induced redox difference spectroscopy. We obtained relatively high values of > 250 mV both for the MoVI–MoV redox couple and the heme b cofactor, whereas FS2 is only reduced at a very low redox potential, causing magnetic coupling with the neighboring FS1 and FS3. We compare the results with the data on related enzymes and interpret their significance for the function of EbDH. Graphical abstract

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Section: Heme B Cofactorsupporting

confidence: 84%

Characterisation of the redox centers of ethylbenzene dehydrogenase

et al. 2021

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“…One of the more recently discovered Mo-enzymes is ethylbenzene dehydrogenase (EBDH) isolated from the β-proteobacterium Aromatoleum aromaticum, which is involved in the direct anaerobic oxidation of nonactivated ethylbenzene to 1-( S )-phenylethanol. − Furthermore, EBDH catalytically converts a broad spectrum of aromatic and heterocyclic compounds with ethyl or propyl substituents to their secondary alcohols with high enantioselectivity, and thus it is potentially useful in the generation of precursors to fine chemicals. − It is the first known enzyme capable of the direct anaerobic oxidation of nonactivated hydrocarbons …”

Section: Introductionmentioning

confidence: 99%

Electrocatalytic Hydrocarbon Hydroxylation by Ethylbenzene Dehydrogenase from Aromatoleum aromaticum

et al. 2015

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We report the electrocatalytic activity of ethylbenzene dehydrogenase (EBDH) from the β-proteobacterium Aromatoleum aromaticum. EBDH is a complex 155 kDa heterotrimeric molybdenum/iron-sulfur/heme protein which catalyzes the enantioselective hydroxylation of nonactivated ethylbenzene to (S)-1-phenylethanol without molecular oxygen as cosubstrate. Furthermore, it oxidizes a wide range of other alkyl-substituted aromatic and heterocyclic compounds to their secondary alcohols. Hydroxymethylferrocenium (FM) is used as an artificial electron acceptor for EBDH in an electrochemically driven catalytic system. Electrocatalytic activity of EBDH is demonstrated with both its native substrate ethylbenzene and the related substrate p-ethylphenol. The catalytic system has been modeled by electrochemical simulation across a range of sweep rates and concentrations of each substrate, which provides new insights into the kinetics of the EBDH catalytic mechanism.

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“…EBDH hydroxylates ethylbenzene to enantiomerically pure (S) -1-phenylethanol. Water has been proven as the source of the hydroxyl group [Ball et al, 1996], while the abstracted electrons are transferred either to cytochrome c [Szaleniec et al, 2003] or to artificial electron acceptors of relatively high redox potential, for example ferricenium [Kniemeyer and Heider, 2001a, b] or ferricyanide [Tataruch et al, 2014].…”

Section: Ethylbenzene Dehydrogenase In Anaerobic Ethylbenzene Metabolismmentioning

confidence: 99%

“…Almost all of these substrates are turned over in a highly enantiospecific manner, producing usually the same (S) -conformation of the products as observed for ethylbenzene. This property is principally very interesting for the industrial production of chiral alcohols in a completely new process by hydroxylating the respective hydrocarbons instead of the established process of reducing ketones by stereospecific alcohol dehydrogenases [Tataruch et al, 2014]. Because of the complexity of EDBH and its fast inactivation in air as an isolated enzyme, this process is only feasible with immobilized enzyme or in whole-cell reactors.…”

Section: Structural Propertiesmentioning

confidence: 99%

“…Because of the complexity of EDBH and its fast inactivation in air as an isolated enzyme, this process is only feasible with immobilized enzyme or in whole-cell reactors. It has indeed recently been demonstrated that ethylbenzene can be converted to (S) -1-phenylethanol to a considerable amount in such a process [Tataruch et al, 2014].…”

Section: Structural Propertiesmentioning

confidence: 99%

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Ethylbenzene Dehydrogenase and Related Molybdenum Enzymes Involved in Oxygen-Independent Alkyl Chain Hydroxylation

et al. 2016

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Ethylbenzene dehydrogenase initiates the anaerobic bacterial degradation of ethylbenzene and propylbenzene. Although the enzyme is currently only known from a few closely related denitrifying bacterial strains affiliated to the Rhodocyclaceae, it clearly marks a universally occurring mechanism used for attacking recalcitrant substrates in the absence of oxygen. Ethylbenzene dehydrogenase belongs to subfamily 2 of the DMSO reductase-type molybdenum enzymes together with paralogous enzymes involved in the oxygen-independent hydroxylation of p-cymene, the isoprenoid side chains of sterols and even possibly n-alkanes; the subfamily also extends to dimethylsulfide dehydrogenases, selenite, chlorate and perchlorate reductases and, most significantly, dissimilatory nitrate reductases. The biochemical, spectroscopic and structural properties of the oxygen-independent hydroxylases among these enzymes are summarized and compared. All of them consist of three subunits, contain a molybdenum-bis-molybdopterin guanine dinucleotide cofactor, five Fe-S clusters and a heme b cofactor of unusual ligation, and are localized in the periplasmic space as soluble enzymes. In the case of ethylbenzene dehydrogenase, it has been determined that the heme b cofactor has a rather high redox potential, which may also be inferred for the paralogous hydroxylases. The known structure of ethylbenzene dehydrogenase allowed the calculation of detailed models of the reaction mechanism based on the density function theory as well as QM-MM (quantum mechanics - molecular mechanics) methods, which yield predictions of mechanistic properties such as kinetic isotope effects that appeared consistent with experimental data.

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Suitability of the hydrocarbon-hydroxylating molybdenum-enzyme ethylbenzene dehydrogenase for industrial chiral alcohol production

Cited by 15 publications

References 35 publications

Characterisation of the redox centers of ethylbenzene dehydrogenase

Characterisation of the redox centers of ethylbenzene dehydrogenase

Electrocatalytic Hydrocarbon Hydroxylation by Ethylbenzene Dehydrogenase from Aromatoleum aromaticum

Ethylbenzene Dehydrogenase and Related Molybdenum Enzymes Involved in Oxygen-Independent Alkyl Chain Hydroxylation

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