Genetic and molecular organization of the alkylbenzene catabolism operon in the psychrotrophic strain Pseudomonas putida 01G3

The Il-kb sequence encompassing the alkylbenzene upper pathway in Pseudomon as putida 01G3, a psychrotrophic strain able to degrade alkylbenzenes at lo w temperatures, was characterized. Together with a potential regulator (Ebd R), six putative enzymes (EbdAaAbAcAdBC) were identified, and they exhibite d highly significant similarities with enzymes implicated in the equivalent pathway in P. putida RE204. ebd genes appeared to be preferentially induce d by ethylbenzene. Multiple-alignment data and growth rate measurements led us to classify 01G3 and closely related strains in two groups with distinc t substrate specificities. Close to identified genes, remnants of ISS-like elements provided insight into the evolution of catabolic sequences through rearrangements fi om a less complex ancestral cluster.