Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum

Müller, Jochen A.; Schink, Bernhard

doi:10.1007/s002030000148

Cited by 22 publications

(16 citation statements)

References 46 publications

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“…In vitro assays with glutarate-, benzoate-, and 3-hydroxybenzoate-fermenting bacteria suggested that glutaconylCoA is the product released from glutaryl-CoA dehydrogenase without a concomitant decarboxylation to crotonyl-CoA. The subsequent decarboxylation is then catalyzed by a membrane-bound, sodium ion-pumping glutaconyl-CoA decarboxylase containing a biotin cofactor (15,28,30). In accordance, the genes coding for such a decarboxylase are present in the genome of the benzoate-fermenting organism Syntrophus aciditrophicus (29).…”

mentioning

confidence: 76%

Decarboxylating and Nondecarboxylating Glutaryl-Coenzyme A Dehydrogenases in the Aromatic Metabolism of Obligately Anaerobic Bacteria

et al. 2009

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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 CO 2 . In this work, we studied GDHs from the strictly anaerobic, aromatic compound-degrading organisms Geobacter metallireducens (GDH Geo ) (Fe[III] reducing) and Desulfococcus multivorans (GDH Des ) (sulfate reducing). GDH Geo was purified from cells grown on benzoate and after the heterologous expression of the benzoate-induced bamM gene. The gene coding for GDH Des 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 GDH Geo catalyzed the oxidative decarboxylation of glutaryl-CoA to crotonylCoA at similar rates. In contrast, recombinant GDH Des 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 GDH Geo , the K m was 30 ؎ 2 M and the V max was 3.2 ؎ 0.2 mol min ؊1 mg ؊1 , and for GDH Des , the K m was 52 ؎ 5 M and the V max was 11 ؎ 1 mol min ؊1 mg ؊1 . GDH Des but not GDH Geo 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 GDH Geo but are missing in GDH Des . 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.

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confidence: 76%

Decarboxylating and Nondecarboxylating Glutaryl-Coenzyme A Dehydrogenases in the Aromatic Metabolism of Obligately Anaerobic Bacteria

et al. 2009

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“…been reported, e.g., in the 3-hydroxybenzoate degradation pathway from the fermenting bacterium Sporotomaculum hydroxybenzoicum (259) or in the peripheral toluene degradation pathway (218) (see below).…”

Section: Benzoate Catabolism: the Benzoyl-coa Degradation Pathwaymentioning

confidence: 99%

“…As the first step in the degradation pathway, 3-hydroxybenzoate was activated to 3-hydroxybenzoyl-CoA in a CoA transferase-mediated reaction with acetyl-CoA or butyryl-CoA as the CoA donor. The use of a CoA transferase rather than a CoA ligase (ATP-consuming) reaction for substrate activation has important energetic implications for this fermenting bacterium and constitutes an important exception to the general principle of the activation of aromatic acid compounds by CoA ligases (259). A third pathway for anaerobic 3-hydroxybenzoate degradation that involves hydroxylation reactions to form HHQ has been reported for the denitrifying bacterium strain BoNHB (320).…”

Section: -Hydroxybenzoate Catabolismmentioning

confidence: 99%

Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View

Carmona

Zamarro

Blázquez

et al. 2009

Microbiol Mol Biol Rev

387

381

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SUMMARY Aromatic compounds belong to one of the most widely distributed classes of organic compounds in nature, and a significant number of xenobiotics belong to this family of compounds. Since many habitats containing large amounts of aromatic compounds are often anoxic, the anaerobic catabolism of aromatic compounds by microorganisms becomes crucial in biogeochemical cycles and in the sustainable development of the biosphere. The mineralization of aromatic compounds by facultative or obligate anaerobic bacteria can be coupled to anaerobic respiration with a variety of electron acceptors as well as to fermentation and anoxygenic photosynthesis. Since the redox potential of the electron-accepting system dictates the degradative strategy, there is wide biochemical diversity among anaerobic aromatic degraders. However, the genetic determinants of all these processes and the mechanisms involved in their regulation are much less studied. This review focuses on the recent findings that standard molecular biology approaches together with new high-throughput technologies (e.g., genome sequencing, transcriptomics, proteomics, and metagenomics) have provided regarding the genetics, regulation, ecophysiology, and evolution of anaerobic aromatic degradation pathways. These studies revealed that the anaerobic catabolism of aromatic compounds is more diverse and widespread than previously thought, and the complex metabolic and stress programs associated with the use of aromatic compounds under anaerobic conditions are starting to be unraveled. Anaerobic biotransformation processes based on unprecedented enzymes and pathways with novel metabolic capabilities, as well as the design of novel regulatory circuits and catabolic networks of great biotechnological potential in synthetic biology, are now feasible to approach.

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“…This would allow further metabolism to acetyl-CoA through the benzoyl-CoA pathway (8). The reductive elimination of the m-hydroxyl group has only been demonstrated so far in a fermenting bacterium, Sporotomaculum hydroxybenzoicum (11,27) (Fig. 7B).…”

Section: Discussionmentioning

confidence: 94%

“…It remains to be shown which isomeric form of the dienoyl-CoA is formed. The genes coding for benzoyl-CoA reductase, for the electron donor ferredoxin, and (11,27). (C) Denitrifying strain BoNHB (33).…”

Section: Discussionmentioning

confidence: 99%

Anaerobic Metabolism of 3-Hydroxybenzoate by the Denitrifying Bacterium Thauera aromatica

et al. 2001

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The anaerobic metabolism of 3-hydroxybenzoate was studied in the denitrifying bacterium Thauera aromatica. Cells grown with this substrate were adapted to grow with benzoate but not with 4-hydroxybenzoate. Vice versa, 4-hydroxybenzoate-grown cells did not utilize 3-hydroxybenzoate. The first step in 3-hydroxybenzoate metabolism is a coenzyme A (CoA) thioester formation, which is catalyzed by an inducible 3-hydroxybenzoate-CoA ligase. The enzyme was purified and characterized. Further metabolism of 3-hydroxybenzoylCoA by cell extract required MgATP and was coupled to the oxidation of 2 mol of reduced viologen dyes per mol of substrate added. Purification of the 3-hydroxybenzoyl-CoA reducing enzyme revealed that this activity was due to benzoyl-CoA reductase, which reduced the 3-hydroxy analogue almost as efficiently as benzoyl-CoA. The further metabolism of the alicyclic dienoyl-CoA product containing the hydroxyl substitution obviously required additional specific enzymes. Comparison of the protein pattern of 3-hydroxybenzoate-grown cells with benzoate-grown cells revealed several 3-hydroxybenzoate-induced proteins; the N-terminal amino acid sequences of four induced proteins were determined and the corresponding genes were identified and sequenced. A cluster of six adjacent genes contained the genes for substrate-induced proteins 1 to 3; this cluster may not yet be complete. Protein 1 is a short-chain alcohol dehydrogenase. Protein 2 is a member of enoyl-CoA hydratase enzymes. Protein 3 was identified as 3-hydroxybenzoate-CoA ligase. Protein 4 is another member of the enoyl-CoA hydratases. In addition, three genes coding for enzymes of ␤-oxidation were present. The anaerobic 3-hydroxybenzoate metabolism here obviously combines an enzyme (benzoyl-CoA reductase) and electron carrier (ferredoxin) of the general benzoyl-CoA pathway with enzymes specific for the 3-hydroxybenzoate pathway. This raises some questions concerning the regulation of both pathways.Phenolic compounds comprise a large and diverse group of organic, water-soluble compounds that can serve as growth substrates for microorganisms. In recent years, it has been established that bacteria can make use of these compounds as carbon and energy source both aerobically and under anoxic conditions. Aerobic metabolism of phenolic compounds requires molecular oxygen and oxygenases for the cleavage of the aromatic ring (for a recent review, see reference 19). Anaerobic metabolism differs in several aspects; most importantly, it is by definition an oxygen-independent process. Phenolic compounds such as phenol or o-cresol are converted to the corresponding hydroxybenzoic acids 4-hydroxybenzoate and 3-methyl-4-hydroxybenzoate by para carboxylation (reviewed in references 18, 21, and 36). Hydroxybenzoic acids are also formed from other aromatic compounds by bacteria; e.g., p-cresol is oxidized to 4-hydroxybenzoate, and m-cresol is oxidized to 3-hydroxybenzoate (7, 33).It appears that there are at least four ways to metabolize hydroxybenzoic acids further under an...

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Initial steps in the fermentation of 3-hydroxybenzoate by Sporotomaculum hydroxybenzoicum

Cited by 22 publications

References 46 publications

Decarboxylating and Nondecarboxylating Glutaryl-Coenzyme A Dehydrogenases in the Aromatic Metabolism of Obligately Anaerobic Bacteria

Decarboxylating and Nondecarboxylating Glutaryl-Coenzyme A Dehydrogenases in the Aromatic Metabolism of Obligately Anaerobic Bacteria

Anaerobic Catabolism of Aromatic Compounds: a Genetic and Genomic View

Anaerobic Metabolism of 3-Hydroxybenzoate by the Denitrifying Bacterium Thauera aromatica

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