A Partial Order for Genes Determining Enzymes of the meta-Cleavage Pathway in Pseudomonas putida

Abstract

A partial order for genes which specify meta-cleavage pathway enzymes was derived from properties of a polarity mutant strain (PsU5) of P. putida NC1B10015 and a partial revertant, PsU5/R21. The polar mutation is within the 2-hydroxymuconic semialdehyde dehydrogenase gene and results in loss of detectable 2-hydroxymuconic semialdehyde hydrolase and 90-95% reduction in the activities of 4-oxalocrotonate tautomerase, 4-oxalocrotonate decarboxylase, 2-oxopent-4-enoate hydratase and 4-hydroxy-2-oxovalerate aldolase. The partial revertant PsU5/R21 regained wild-type levels of all enzymes except the aldehyde dehydrogenase. It is probable that all genes determining the dehydrogenase and subsequent enzymes are transcribed as a polycistronic message. This is the first report of mapping genes determining the enzymes of the meta-cleavage pathway.