Importance of different tfd genes for degradation of chloroaromatics by Ralstonia eutropha JMP134

Iris Plumeier, Danilo Pérez-Pantoja, Sabina Heim, Bernardo González, Dietmar H. Pieper

Research output: Contribution to journalArticlepeer-review

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The tfdCIDIEIFI, and tfdDIICIIEIIFII 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 tfdI-encoded enzymes was usually higher than that of tfdII-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 tfdDII-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.

Original languageEnglish
Pages (from-to)4054-4064
Number of pages11
JournalJournal of Bacteriology
Issue number15
StatePublished - 2002


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