Cloning and sequencing of a 2,5-dichlorohydroquinone reductive dehalogenase gene whose product is involved in degradation of gamma-hexachlorocyclohexane by Sphingomonas paucimobilis

J Bacteriol. 1998 Mar;180(6):1354-9. doi: 10.1128/JB.180.6.1354-1359.1998.


Sphingomonas (formerly Pseudomonas) paucimobilis UT26 utilizes gamma-hexachlorocyclohexane (gamma-HCH), a halogenated organic insecticide, as a sole carbon and energy source. In a previous study, we showed that gamma-HCH is degraded to 2,5-dichlorohydroquinone (2,5-DCHQ) (Y. Nagata, R. Ohtomo, K. Miyauchi, M. Fukuda, K. Yano, and M. Takagi, J. Bacteriol. 176:3117-3125, 1994). In the present study, we cloned and characterized a gene, designated linD, directly involved in the degradation of 2,5-DCHQ. The linD gene encodes a peptide of 343 amino acids and has a low level of similarity to proteins which belong to the glutathione S-transferase family. When LinD was overproduced in Escherichia coli, a 40-kDa protein was found after sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Northern blot analysis revealed that expression of the linD gene was induced by 2,5-DCHQ in S. paucimobilis UT26. Thin-layer chromatography and gas chromatography-mass spectrometry analyses with the LinD-overexpressing E. coli cells revealed that LinD converts 2,5-DCHQ rapidly to chlorohydroquinone (CHQ) and also converts CHQ slowly to hydroquinone. LinD activity in crude cell extracts was increased 3.7-fold by the addition of glutathione. All three of the Tn5-induced mutants of UT26, which lack 2,5-DCHQ dehalogenase activity, had rearrangements or a deletion in the linD region. These results indicate that LinD is a glutathione-dependent reductive dehalogenase involved in the degradation of gamma-HCH by S. paucimobilis UT26.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Bacterial Proteins*
  • Base Composition
  • Blotting, Northern
  • Chromatography, Gas
  • Chromatography, Thin Layer
  • Cloning, Molecular
  • DNA Transposable Elements
  • DNA, Bacterial / analysis
  • DNA, Bacterial / genetics
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Gene Expression
  • Gene Library
  • Glutathione / metabolism
  • Glutathione Transferase / genetics
  • Hexachlorocyclohexane / metabolism*
  • Hydrolases / genetics*
  • Hydroquinones / metabolism
  • Molecular Sequence Data
  • Plasmids
  • Pseudomonas / genetics*
  • Restriction Mapping
  • Sequence Alignment
  • Sequence Analysis, DNA
  • Sequence Deletion
  • Sequence Homology, Amino Acid
  • Sodium Dodecyl Sulfate / pharmacology


  • Bacterial Proteins
  • DNA Transposable Elements
  • DNA, Bacterial
  • Hydroquinones
  • Sodium Dodecyl Sulfate
  • Hexachlorocyclohexane
  • 2,5-dichlorohydroquinone
  • Glutathione Transferase
  • Hydrolases
  • LinD protein, Pseudomonas paucimobilis
  • Glutathione

Associated data

  • GENBANK/D89733