Characterization of genes for enzymes involved in the phenanthrene degradation in Nocardioides sp. KP7

The nucleotide sequence of the gene cluster, phdEFABGHCD, encoding enzymes responsible for the transformation of phenanthrene to 1-hydroxy-2-naphthoat e in Nocardioides sp. strain KP7 was determined. This gene cluster, which m ay constitute a single operon, resided at 6.1-kb downstream of the phdIJK g ene cluster encoding the enzymes for the transformation of 1-hydroxy-2-naph thoate to o-phthalate. In general, the phd products exhibited moderate degr ees of homology with isofunctional enzymes found in pathways for the degrad ation of other aromatic compounds. Remarkably, the phdC gene product had fe atures of the [3Fe-4S] type ferredoxin, which has not been found so far as a component of the ring-hydroxylating dioxygenase. Escherichia coli carryin g the genes for phenanthrene dioxygenase, phdABCD, was capable to oxidize p henanthrene.