Benzoate-coenzyme A ligase from Thauera aromatica: an enzyme acting in anaerobic and aerobic pathways

J Bacteriol. 2003 Aug;185(16):4920-9. doi: 10.1128/jb.185.16.4920-4929.2003.

Abstract

In the denitrifying member of the beta-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)/K(m), 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Aerobiosis
  • Anaerobiosis
  • Benzoates / metabolism
  • Cloning, Molecular
  • Coenzyme A Ligases / genetics
  • Coenzyme A Ligases / metabolism*
  • Gene Expression Regulation, Bacterial*
  • Molecular Sequence Data
  • Nitrates / metabolism
  • Sequence Analysis, DNA
  • Thauera / enzymology*
  • Thauera / growth & development*

Substances

  • Benzoates
  • Nitrates
  • 2-aminobenzoate coenzyme A ligase
  • Coenzyme A Ligases
  • benzoate coenzyme A ligase

Associated data

  • GENBANK/AF373594