title: Importance of different tfd genes for degradation of chloroaromatics by Ralstonia eutropha JMP134.
abstract: The tfdC(I)D(I)E(I)F(I,) and tfdD(II)C(II)E(II)F(II) gene modules of plasmid pJP4 of Ralstonia eutropha JMP134 encode complete sets of functional enzymes for the transformation of chlorocatechols into 3-oxoadipate, which are all expressed during growth on 2,4-dichlorophenoxyacetate (2,4-D). However, activity of tfd(I)-encoded enzymes was usually higher than that of tfd(II)-encoded enzymes, both in the wild-type strain grown on 2,4-D and in 3-chlorobenzoate-grown derivatives harboring only one tfd gene module. The tfdD(II)-encoded chloromuconate cycloisomerase exhibited special kinetic properties, with high activity against 3-chloromuconate and poor activity against 2-chloromuconate and unsubstituted muconate, thus explaining the different phenotypic behaviors of R. eutropha strains containing different tfd gene modules. The enzyme catalyzes the formation of an equilibrium between 2-chloromuconate and 5-chloro- and 2-chloromuconolactone and very inefficiently catalyzes dehalogenation to form trans-dienelactone as the major product, thus differing from all (chloro)muconate cycloisomerases described thus far.
authors.affiliation: Department of Environmental Biotechnology, GBF-German Research Center for Biotechnology, D-38124 Braunschweig, Germany.
authors.forename: Iris
authors.initials: I
authors.lastname: Plumeier
authors.forename: Danilo
authors.initials: D
authors.lastname: Pérez-Pantoja
authors.forename: Sabina
authors.initials: S
authors.lastname: Heim
authors.forename: Bernardo
authors.initials: B
authors.lastname: González
authors.forename: Dietmar H
authors.initials: DH
authors.lastname: Pieper
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000378:metabolism; D000272:Adipates / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000235:genetics / Q000378:metabolism*; D002396:Catechols / Q000378:metabolism; D002723:Chlorobenzoates / Q000378:metabolism; D003470:Culture Media; D020118:Cupriavidus necator / Q000201:enzymology / Q000235:genetics*; D049308:Dioxygenases; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D019753:Intramolecular Lyases / Q000235:genetics / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism*; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D044925:Oxidoreductases Acting on CH-CH Group Donors; D010105:Oxygenases / Q000235:genetics / Q000378:metabolism*; D010957:Plasmids; D013011:Sorbic Acid / Q000031:analogs & derivatives* / Q000378:metabolism
chemical_list: D000272:Adipates; D002396:Catechols; D002723:Chlorobenzoates; D003470:Culture Media; C036427:3-chlorobenzoic acid; D015084:2,4-Dichlorophenoxyacetic Acid; C088140:2-chloromuconic acid; C005939:muconic acid; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D010105:Oxygenases; D049308:Dioxygenases; C044173:chlorocatechol 1,2-dioxygenase; C084087:2,4-dichlorophenoxyacetate-alpha-ketoglutarate dioxygenase; D044925:Oxidoreductases Acting on CH-CH Group Donors; C021530:maleylacetate reductase; D002265:Carboxylic Ester Hydrolases; C046130:carboxymethylenebutenolidase; D019753:Intramolecular Lyases; C055773:chloromuconate cycloisomerase; D013011:Sorbic Acid