STRUCTURE OF THE PCBC GENE ENCODING 2,3-DIHYDROXYBIPHENYL DIOXYGENASEOF PSEUDOMONAS SP P20

Pseudomonas sp. P20 is a soil bacterium growing in biphenyl or 4-chlor obiphenyl as the sole carbon and energy source, where the initial cata bolism of biphenyl to form benzoate is catalyzed by four enzymes encod ed in the pcbABCD gene cluster. The nucleotide sequence of the 2,3-dih ydroxybiphenyl dioxygenase gene corresponding to the pcbC gene was det ermined. The pcbC gene was composed of 921 base pairs with an ATG init iation codon and a TGA termination codon, which can encode a polypepti de of molecular mass 34 kDa containing 306 amino acids. A promoter-lik e sequence and ribosome-binding sequence were identified upstream of t he initiation codon. The deduced amino acid sequence of 2,3-dihydroxyb iphenyl dioxygenase exhibited 47% identity with that of corresponding enzyme of Pseudomonas sp. DJ-12, and less than 35% identity with those of other extradiol-type dioxygenases. (C) 1996 Academic Press, Inc.