The glutathione S-transferase OrfE3 of the dioxin-degrading bacterium sphingomonas sp RW1 displays maleylpyruvate isomerase activity

A GST gene of unknown function, orfE3, was earlier detected in one of the g ene clusters responsible for dibenzofuran degradation by sphingomonas sp. R W1 The degradation pathway for dibenzofuran in strain RW1 proceeds through salicylate and gentisate into intermediate metabolism. Using gentisate diox ygenase from Sphingomonas sp. RW5 to generate maleylpyruvate from gentisate , the OrfE3 protein of strain RW1 was shown to gen display maleylpyruvate i somerase activity. However, data obtained with an orfE3-specific chromosoma l knockout mutant of strain RW1 suggest that the orfE3 GST gene is not esse ntial for growth of strain RW1 with dibenzofuran, salicylate or gentisate. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved.