Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1128/JB.00205-09 |
| Title (Primary) | Decarboxylating and nondecarboxylating glutaryl-coenzyme A dehydrogenases in the aromatic metabolism of obligately anaerobic bacteria |
| Author | Wischgoll, S.; Taubert, M.; Peters, F.; Jehmlich, N.
; von Bergen, M.; Boll, M. |
| Source Titel | Journal of Bacteriology |
| Year | 2009 |
| Department | METABOX; PROTEOM |
| Volume | 191 |
| Issue | 13 |
| Page From | 4401 |
| Page To | 4409 |
| Language | englisch |
| Abstract | In anaerobic bacteria using aromatic growth substrates, glutaryl-coenzyme A (CoA) dehydrogenases (GDHs) are involved in the catabolism of the central intermediate benzoyl-CoA to three acetyl-CoAs and CO2. In this work, we studied GDHs from the strictly anaerobic, aromatic compound-degrading organisms Geobacter metallireducens (GDHGeo) (Fe[III] reducing) and Desulfococcus multivorans (GDHDes) (sulfate reducing). GDHGeo was purified from cells grown on benzoate and after the heterologous expression of the benzoate-induced bamM gene. The gene coding for GDHDes was identified after screening of a cosmid gene library. Reverse transcription-PCR revealed that its expression was induced by benzoate; the product was heterologously expressed and isolated. Both wild-type and recombinant GDHGeo catalyzed the oxidative decarboxylation of glutaryl-CoA to crotonyl-CoA at similar rates. In contrast, recombinant GDHDes catalyzed only the dehydrogenation to glutaconyl-CoA. The latter compound was decarboxylated subsequently to crotonyl-CoA by the addition of membrane extracts from cells grown on benzoate in the presence of 20 mM NaCl. All GDH enzymes were purified as homotetramers of a 43- to 44-kDa subunit and contained 0.6 to 0.7 flavin adenine dinucleotides (FADs)/monomer. The kinetic properties for glutaryl-CoA conversion were as follows: for GDHGeo, the K was 30 ± 2 µM and the Vmax was 3.2 ± 0.2 µmol min-1 mg-1, and for GDHDes, the K was 52 ± 5 µM and the Vmax was 11 ± 1 µmol min-1 mg-1. GDHDes but not GDHGeo was inhibited by glutaconyl-CoA. Highly conserved amino acid residues that were proposed to be specifically involved in the decarboxylation of the intermediate glutaconyl-CoA were identified in GDHGeo but are missing in GDHDes. The differential use of energy-yielding/energy-demanding enzymatic processes in anaerobic bacteria that degrade aromatic compounds is discussed in view of phylogenetic relationships and constraints of overall energy metabolism. |
| Wischgoll, S., Taubert, M., Peters, F., Jehmlich, N., von Bergen, M., Boll, M. (2009): Decarboxylating and nondecarboxylating glutaryl-coenzyme A dehydrogenases in the aromatic metabolism of obligately anaerobic bacteria J. Bacteriol. 191 (13), 4401 - 4409 10.1128/JB.00205-09 |
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