Importance of DifferenttfdGenes for Degradation of Chloroaromatics byRalstonia eutrophaJMP134

Publisher Website
Google Scholar
Abstract
ThetfdCIDIEIFI,andtfdDIICIIEIIFIIgene modules of plasmid pJP4 ofRalstonia eutrophaJMP134 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 oftfdI-encoded enzymes was usually higher than that oftfdII-encoded enzymes, both in the wild-type strain grown on 2,4-D and in 3-chlorobenzoate-grown derivatives harboring only onetfdgene module. ThetfdDII-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 ofR. eutrophastrains containing differenttfdgene modules. The enzyme catalyzes the formation of an equilibrium between 2-chloromuconate and 5-chloro- and 2-chloromuconolactone and very inefficiently catalyzes dehalogenation to formtrans-dienelactone as the major product, thus differing from all (chloro)muconate cycloisomerases described thus far.

This publication has 77 references indexed in Scilit: