Details zur Publikation

Referenztyp Zeitschriften
DOI / URL Link
Titel (primär) Aromatizing cyclohexa-1,5-diene-1-carbonyl-coenzyme A oxidase. Characterization and its role in anaerobic aromatic metabolism
Autor Thiele, B.; Rieder, O.; Jehmlich, N.; von Bergen, M.; Müller, M.; Boll, M.;
Journal / Serie Journal of Biological Chemistry
Erscheinungsjahr 2008
Department PROTEOM;
Band/Volume 283
Heft 30
Sprache englisch;
Abstract Benzoyl-CoA reductases (BCRs) are key enzymes of anaerobic aromatic metabolism in facultatively anaerobic bacteria. The highly oxygen-sensitive enzymes catalyze the ATP-dependent reductive dearomatization of the substrate, yielding cyclohexa-1,5-diene-1-carbonyl-CoA (1,5-dienoyl-CoA). In extracts from anaerobically grown denitrifying Thauera aromatica, we detected a benzoate-induced, benzoyl-CoA-forming, 1,5-dienoyl-CoA:acceptor oxidoreductase activity. This activity co-purified with BCR but could be partially separated from it by hydroxyapatite chromatography. After activity staining on native gels, a monomeric protein with a subunit molecular weight of Mr 76,000 was identified. Mass spectrometric analysis of tryptic digests identified peptides from NADH oxidases/2,4-dienoyl-CoA reductases/“old yellow” enzymes. The UV-visible spectrum of the enriched enzyme suggested the presence of flavin and Fe/S-cofactors, and it was bleached upon the addition of 1,5-dienoyl-CoA. The enzyme had a high affinity for dioxygen as electron acceptor (Km = 10 μm) and therefore is referred to as 1,5-dienoyl-CoA oxidase (DCO). The likely product formed from dioxygen reduction was H2O. DCO was highly specific for 1,5-dienoyl-CoA (Km = 27 μm). The initial rate of DCO followed a Nernst curve with half-maximal activity at +10 mV. We propose that DCO provides protection for the extremely oxygen-sensitive BCR enzyme when the bacterium degrades aromatic compounds at the edge of steep oxygen gradients. The redox-dependent switch in DCO guarantees that DCO is only active during oxidative stress and circumvents futile dearomatization/rearomatization reactions catalyzed by BCR and DCO.
ID 1515
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=1515
Thiele, B., Rieder, O., Jehmlich, N., von Bergen, M., Müller, M., Boll, M. (2008):
Aromatizing cyclohexa-1,5-diene-1-carbonyl-coenzyme A oxidase. Characterization and its role in anaerobic aromatic metabolism
J. Biol. Chem. 283 (30), 20713 - 20721