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Ethylbenzene Dehydrogenase and Related Molybdenum Enzymes Involved in Oxygen-Independent Alkyl Chain Hydroxylation.
- Source :
-
Journal of molecular microbiology and biotechnology [J Mol Microbiol Biotechnol] 2016; Vol. 26 (1-3), pp. 45-62. Date of Electronic Publication: 2016 Mar 10. - Publication Year :
- 2016
-
Abstract
- 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.<br /> (© 2016 S. Karger AG, Basel.)
- Subjects :
- Alkanes metabolism
Anaerobiosis
Bacteria, Anaerobic enzymology
Biodegradation, Environmental
Cholesterol chemistry
Cholesterol metabolism
Coenzymes chemistry
Hydroxylation
Metalloproteins chemistry
Mixed Function Oxygenases chemistry
Mixed Function Oxygenases metabolism
Models, Molecular
Molybdenum Cofactors
Oxidoreductases genetics
Pteridines chemistry
Rhodocyclaceae enzymology
Rhodocyclaceae metabolism
Coenzymes metabolism
Metalloproteins metabolism
Oxidoreductases chemistry
Oxidoreductases metabolism
Oxygen metabolism
Pteridines metabolism
Subjects
Details
- Language :
- English
- ISSN :
- 1660-2412
- Volume :
- 26
- Issue :
- 1-3
- Database :
- MEDLINE
- Journal :
- Journal of molecular microbiology and biotechnology
- Publication Type :
- Academic Journal
- Accession number :
- 26960184
- Full Text :
- https://doi.org/10.1159/000441357