NADPH-dependent Reductive Ortho Dehalogenation of 2,4-dichlorobenzoic Acid in Corynebacterium Sepedonicum KZ-4 and Coryneform Bacterium strainNTB-1 via 2,4-dichlorobenzoyl Coenzyme A

J Bacteriol. 1996 May;178(9):2656-61. doi: 10.1128/jb.178.9.2656-2661.1996.

Abstract

Corynebacterium sepedonicum KZ-4, described earlier as a strain capable of growth on 2,4-dichlorobenzoate (G.M. Zaitsev and Y.N. Karasevich, Mikrobiologiya 54:356-369, 1985), is known to metabolize this substrate via 4-hydroxybenzoate and protocatechuate, and evidence consistent with an initial reductive dechlorination step to form 4-chlorobenzoate was found in another coryneform bacterium, strain NTB-1 (W.J.J. van den Tweel, J.B. Kok, and J.A.M. de Bont, Appl. Environ. Microbiol. 53:810-815, 1987). 2-Chloro-4-fluorobenzoate was found to be converted stoichiometrically to 4-fluorobenzoate by resting cells of strain KZ-4, compatible with a reductive process. Experiments with cell extracts demonstrated that Mg - ATP and coenzyme A (CoA) were required to stimulate reductive dehalogenation, consistent with the intermediacy of 2-chloro-4-fluoro-benzoyl-CoA and 2,4-dichlorobenzoyl-CoA thioesters. 2,4-Dichlorobenzoyl-CoA was shown to be converted to 4-chlorobenzoyl-CoA in a novel NADPH-dependent reaction in extracts of both KZ-4 and NTB-1. In addition to the ligase and reductive dehalogenase activities, hydrolytic 4-chlorobenzoyl-CoA dehalogenase and thioesterase activities, 4-hydroxybenzoate 3-monooxygenase, and protocatechuate 3,4-dioxygenase activities were demonstrated to be present in the soluble fraction of KZ-4 extracts following ultracentrifugation. We propose that the pathway for 2,4-dichlorobenzoate catabolism in strains KZ-4 and NTB-1 involves formation of 2,4-dichlorobenzoyl-CoA, NADPH-dependent ortho dehalogenation yielding 4-chlorobenzoyl-CoA, hydrolytic removal of chlorine from the para position to generate 4-hydroxybenzoyl-CoA, hydrolysis to form 4-hydroxybenzoate, oxidation to yield protocatechuate, and oxidative ring cleavage.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alcaligenes / enzymology*
  • Benzoates* / metabolism
  • Biodegradation, Environmental
  • Chlorine / metabolism
  • Chlorobenzoates / metabolism*
  • Coenzyme A / metabolism*
  • Coenzyme A Ligases / metabolism
  • Corynebacterium / enzymology*
  • Hydrolases / metabolism
  • Mixed Function Oxygenases / metabolism
  • NADP / metabolism
  • Oxygenases / metabolism
  • Thiolester Hydrolases / metabolism

Substances

  • Benzoates
  • Chlorobenzoates
  • 2,4-dichlorobenzoic acid
  • Chlorine
  • NADP
  • Mixed Function Oxygenases
  • Oxygenases
  • Hydrolases
  • Thiolester Hydrolases
  • 4-chlorobenzoyl coenzyme A dehalogenase
  • 4-halobenzoate-CoA ligase
  • Coenzyme A Ligases
  • 4-chlorobenzoic acid
  • Coenzyme A
  • 4-fluorobenzoic acid