PMID- 16597983
OWN - NLM
STAT- MEDLINE
DCOM- 20060628
LR  - 20181113
IS  - 0099-2240 (Print)
IS  - 1098-5336 (Electronic)
IS  - 0099-2240 (Linking)
VI  - 72
IP  - 4
DP  - 2006 Apr
TI  - Chlorophenol hydroxylases encoded by plasmid pJP4 differentially contribute to 
      chlorophenoxyacetic acid degradation.
PG  - 2783-92
AB  - Phenoxyalkanoic compounds are used worldwide as herbicides. Cupriavidus necator 
      JMP134(pJP4) catabolizes 2,4-dichlorophenoxyacetate (2,4-D) and 
      4-chloro-2-methylphenoxyacetate (MCPA), using tfd functions carried on plasmid 
      pJP4. TfdA cleaves the ether bonds of these herbicides to produce 
      2,4-dichlorophenol (2,4-DCP) and 4-chloro-2-methylphenol (MCP), respectively. 
      These intermediates can be degraded by two chlorophenol hydroxylases encoded by 
      the tfdB(I) and tfdB(II) genes to produce the respective chlorocatechols. We 
      studied the specific contribution of each of the TfdB enzymes to the 2,4-D/MCPA 
      degradation pathway. To accomplish this, the tfdB(I) and tfdB(II) genes were 
      independently inactivated, and growth on each chlorophenoxyacetate and total 
      chlorophenol hydroxylase activity were measured for the mutant strains. The 
      phenotype of these mutants shows that both TfdB enzymes are used for growth on 
      2,4-D or MCPA but that TfdB(I) contributes to a significantly higher extent than 
      TfdB(II). Both enzymes showed similar specificity profiles, with 2,4-DCP, MCP, 
      and 4-chlorophenol being the best substrates. An accumulation of chlorophenol was 
      found to inhibit chlorophenoxyacetate degradation, and inactivation of the tfdB 
      genes enhanced the toxic effect of 2,4-DCP on C. necator cells. Furthermore, 
      increased chlorophenol production by overexpression of TfdA also had a negative 
      effect on 2,4-D degradation by C. necator JMP134 and by a different host, 
      Burkholderia xenovorans LB400, harboring plasmid pJP4. The results of this work 
      indicate that codification and expression of the two tfdB genes in pJP4 are 
      important to avoid toxic accumulations of chlorophenols during phenoxyacetic acid 
      degradation and that a balance between chlorophenol-producing and 
      chlorophenol-consuming reactions is necessary for growth on these compounds.
FAU - Ledger, T
AU  - Ledger T
AD  - Laboratorio de Microbiologia, Departamento de Genetica Molecular y Microbiologia, 
      Facultad de Ciencias Biologicas, Pontificia Universidad Catolica de Chile, 
      Casilla 114-D, Santiago, Chile.
FAU - Pieper, D H
AU  - Pieper DH
FAU - Gonzalez, B
AU  - Gonzalez B
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Appl Environ Microbiol
JT  - Applied and environmental microbiology
JID - 7605801
RN  - 0 (Bacterial Proteins)
RN  - 0 (Chlorophenols)
RN  - 0 (Herbicides)
RN  - 2577AQ9262 (2,4-Dichlorophenoxyacetic Acid)
RN  - D888C394VO (2-Methyl-4-chlorophenoxyacetic Acid)
RN  - EC 1.- (Mixed Function Oxygenases)
SB  - IM
MH  - 2,4-Dichlorophenoxyacetic Acid/*metabolism/pharmacology
MH  - 2-Methyl-4-chlorophenoxyacetic Acid/*metabolism/pharmacology
MH  - Bacterial Proteins/genetics/metabolism
MH  - Biodegradation, Environmental
MH  - Burkholderiaceae/*enzymology/genetics/growth & development
MH  - Chlorophenols/metabolism
MH  - Herbicides/*metabolism/pharmacology
MH  - Mixed Function Oxygenases/*genetics/metabolism
MH  - Plasmids/*genetics
MH  - Substrate Specificity
PMC - PMC1448979
EDAT- 2006/04/07 09:00
MHDA- 2006/06/29 09:00
PMCR- 2006/08/01
CRDT- 2006/04/07 09:00
PHST- 2006/04/07 09:00 [pubmed]
PHST- 2006/06/29 09:00 [medline]
PHST- 2006/04/07 09:00 [entrez]
PHST- 2006/08/01 00:00 [pmc-release]
AID - 72/4/2783 [pii]
AID - 2965-05 [pii]
AID - 10.1128/AEM.72.4.2783-2792.2006 [doi]
PST - ppublish
SO  - Appl Environ Microbiol. 2006 Apr;72(4):2783-92. doi: 
      10.1128/AEM.72.4.2783-2792.2006.