Identification of three novel salicylate 1-hydroxylases involved in the phenanthrene degradation of Sphingobium sp. strain P2

Biochem Biophys Res Commun. 2003 Feb 7;301(2):350-7. doi: 10.1016/s0006-291x(02)03036-x.

Abstract

Five sets of large and small subunits of terminal oxygenase (ahdA1[a-e] and ahdA2[a-e]) and a single gene set encoding ferredoxin (ahdA3) and ferredoxin reductase (ahdA4) were found to be scattered through 15.8- and 14-kb DNA fragments of phenanthrene-degrading Sphingobium sp. strain P2. RT-PCR analysis indicated the inducible and specific expression of ahdA3, ahdA4, and three sets of genes for terminal oxygenase (ahdA1[c-e] and ahdA2[c-e]) in this strain grown on phenanthrene. The biotransformation experiments with resting cells of Escherichia coli JM109 harboring recombinant ahd genes revealed that AhdA2cA1c, AhdA1dA2d, and AhdA1eA2e can all function as a salicylate 1-hydroxylase which converts salicylate, a metabolic intermediate of phenanthrene, to catechol in cooperation with the electron transport proteins AhdA3A4. The first two oxygenases exhibited a broad range of substrate specificities such that they also catalyzed the hydroxylation of methyl- and chloro-substituted salicylates to produce their corresponding substituted catechols.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alphaproteobacteria / enzymology*
  • Alphaproteobacteria / genetics
  • Bacterial Proteins / genetics
  • Bacterial Proteins / metabolism*
  • Biodegradation, Environmental
  • Cloning, Molecular
  • Genes, Bacterial
  • Isoenzymes / genetics
  • Isoenzymes / metabolism*
  • Mixed Function Oxygenases / genetics
  • Mixed Function Oxygenases / metabolism*
  • Mutation
  • Open Reading Frames
  • Phenanthrenes / metabolism*
  • RNA, Ribosomal, 16S / genetics
  • RNA, Ribosomal, 16S / metabolism

Substances

  • Bacterial Proteins
  • Isoenzymes
  • Phenanthrenes
  • RNA, Ribosomal, 16S
  • Mixed Function Oxygenases
  • salicylate 1-monooxygenase