The bzd gene cluster, coding for anaerobic benzoate catabolism, in Azoarcus sp. strain CIB

J Bacteriol. 2004 Sep;186(17):5762-74. doi: 10.1128/JB.186.17.5762-5774.2004.

Abstract

We report here that the bzd genes for anaerobic benzoate degradation in Azoarcus sp. strain CIB are organized as two transcriptional units, i.e., a benzoate-inducible catabolic operon, bzdNOPQMSTUVWXYZA, and a gene, bzdR, encoding a putative transcriptional regulator. The last gene of the catabolic operon, bzdA, has been expressed in Escherichia coli and encodes the benzoate-coenzyme A (CoA) ligase that catalyzes the first step in the benzoate degradation pathway. The BzdA enzyme is able to activate a wider range of aromatic compounds than that reported for other previously characterized benzoate-CoA ligases. The reduction of benzoyl-CoA to a nonaromatic cyclic intermediate is carried out by a benzoyl-CoA reductase (bzdNOPQ gene products) detected in Azoarcus sp. strain CIB extracts. The bzdW, bzdX, and bzdY gene products show significant similarity to the hydratase, dehydrogenase, and ring-cleavage hydrolase that act sequentially on the product of the benzoyl-CoA reductase in the benzoate catabolic pathway of Thauera aromatica. Benzoate-CoA ligase assays and transcriptional analyses based on lacZ-reporter fusions revealed that benzoate degradation in Azoarcus sp. strain CIB is subject to carbon catabolite repression by some organic acids, indicating the existence of a physiological control that connects the expression of the bzd genes to the metabolic status of the cell.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anaerobiosis
  • Artificial Gene Fusion
  • Azoarcus / genetics*
  • Azoarcus / metabolism*
  • Benzoates / metabolism*
  • Biodegradation, Environmental
  • Coenzyme A Ligases / genetics
  • Coenzyme A Ligases / metabolism
  • DNA, Bacterial / chemistry
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression Regulation, Bacterial
  • Genes, Bacterial*
  • Genes, Regulator / genetics
  • Genes, Regulator / physiology
  • Genes, Reporter
  • Hydro-Lyases / genetics
  • Hydrolases / genetics
  • Molecular Sequence Data
  • Multigene Family
  • Operon
  • Oxidoreductases / genetics
  • Oxidoreductases Acting on CH-CH Group Donors / genetics
  • Oxidoreductases Acting on CH-CH Group Donors / metabolism
  • Recombinant Proteins / metabolism
  • Sequence Analysis, DNA
  • Substrate Specificity / physiology
  • Thauera
  • Transcription, Genetic
  • beta-Galactosidase / genetics
  • beta-Galactosidase / metabolism

Substances

  • Benzoates
  • DNA, Bacterial
  • Recombinant Proteins
  • Oxidoreductases
  • Oxidoreductases Acting on CH-CH Group Donors
  • benzoyl-coenzyme A reductase (dearomatizing)
  • Hydrolases
  • beta-Galactosidase
  • Hydro-Lyases
  • Coenzyme A Ligases
  • benzoate coenzyme A ligase

Associated data

  • GENBANK/AF515816
  • GENBANK/AF521665