scholarly journals 6-Hydroxycyclohex-1-ene-1-carbonyl-CoA dehydrogenase and 6-oxocyclohex-1-ene-1-carbonyl-CoA hydrolase, enzymes of the benzoyl-CoA pathway of anaerobic aromatic metabolism in the denitrifying bacterium Thauera aromatica

1999 ◽  
Vol 263 (2) ◽  
pp. 420-429 ◽  
Author(s):  
Diana Laempe ◽  
Martina Jahn ◽  
Georg Fuchs
Keyword(s):  
Denitrifying Bacterium ◽  
Aromatic Metabolism ◽  
Thauera Aromatica ◽  
Anaerobic Aromatic Metabolism ◽  
Coa Hydrolase

Genes coding for the benzoyl-CoA pathway of anaerobic aromatic metabolism in the bacterium Thauera aromatica

1998 ◽  
Vol 256 (1) ◽  
pp. 148-154 ◽  
Author(s):  
Klaus Breese ◽  
Matthias Boll ◽  
Juliane Alt-Morbe ◽  
Hermann Schagger ◽  
Georg Fuchs
Keyword(s):  
Aromatic Metabolism ◽  
Thauera Aromatica ◽  
Anaerobic Aromatic Metabolism

scholarly journals Benzoate-Coenzyme A Ligase from Thauera aromatica: an Enzyme Acting in Anaerobic and Aerobic Pathways

2003 ◽  
Vol 185 (16) ◽  
pp. 4920-4929 ◽  
Author(s):  
Karola Schühle ◽  
Johannes Gescher ◽  
Ulrich Feil ◽  
Michael Paul ◽  
Martina Jahn ◽  
...  
Keyword(s):  
Anaerobic Metabolism ◽  
Coenzyme A ◽  
Aromatic Acids ◽  
Aerobic Growth ◽  
Aromatic Substrates ◽  
Thauera Aromatica ◽  
Coa Ligase ◽  
Anaerobic Aromatic Metabolism ◽  
Coenzyme A Ligase ◽  
Specificity Constant

ABSTRACT In the denitrifying member of the β-Proteobacteria Thauera aromatica, the anaerobic metabolism of aromatic acids such as benzoate or 2-aminobenzoate is initiated by the formation of the coenzyme A (CoA) thioester, benzoyl-CoA and 2-aminobenzoyl-CoA, respectively. Both aromatic substrates were transformed to the acyl-CoA intermediate by a single CoA ligase (AMP forming) that preferentially acted on benzoate. This benzoate-CoA ligase was purified and characterized as a 57-kDa monomeric protein. Based on V max/Km , the specificity constant for 2-aminobenzoate was 15 times lower than that for benzoate; this may be the reason for the slower growth on 2-aminobenzoate. The benzoate-CoA ligase gene was cloned and sequenced and was found not to be part of the gene cluster encoding the general benzoyl-CoA pathway of anaerobic aromatic metabolism. Rather, it was located in a cluster of genes coding for a novel aerobic benzoate oxidation pathway. In line with this finding, the same CoA ligase was induced during aerobic growth with benzoate. A deletion mutant not only was unable to grow anaerobically on benzoate or 2-aminobenzoate, but also aerobic growth on benzoate was affected. This suggests that benzoate induces a single benzoate-CoA ligase. The product of benzoate activation, benzoyl-CoA, then acts as inducer of separate anaerobic or aerobic pathways of benzoyl-CoA, depending on whether oxygen is lacking or present.

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

2001 ◽  
Vol 183 (3) ◽  
pp. 968-979 ◽  
Author(s):  
Diana Laempe ◽  
Martina Jahn ◽  
Klaus Breese ◽  
Hermann Schägger ◽  
Georg Fuchs
Keyword(s):  
Anaerobic Metabolism ◽  
Protein Pattern ◽  
Cell Extract ◽  
Amino Acid Sequences ◽  
Denitrifying Bacterium ◽  
Thauera Aromatica ◽  
Coa Ligase ◽  
Complete Protein ◽  
Coa Reductase ◽  
Induced Proteins

ABSTRACT 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-hydroxybenzoyl-CoA 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 β-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.

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