A Novel Phenanthrene Dioxygenase from Nocardioides sp. Strain KP7: Expression in Escherichia coli

• DOI: 10.1128/jb.182.8.2134-2141.2000
• Publication Date: 2002-07-27T10:03:59Z
• Authors: Atsushi Saito; Tokuro Iwabuchi; Shigeaki Harayama
• Keywords: Dioxygenase; Gene cluster

ABSTRACT Nocardioides sp. strain KP7 grows on phenanthrene but not naphthalene. This organism degrades via 1-hydroxy-2-naphthoate, o -phthalate, and protocatechuate. The genes responsible for the degradation of to -phthalate ( phd ) were found by Southern hybridization reside chromosome. A 10.6-kb DNA fragment containing eight was cloned sequenced. phdA , phdB phdC phdD genes, which encode α β subunits oxygenase component, a ferredoxin, ferredoxin reductase, respectively, dioxygenase identified. gene cluster, phdAB located 8.3 kb downstream previously characterized phdK gene, encodes 2-carboxybenzaldehyde dehydrogenase. phdCD cluster 2.9 gene. PhdA PhdB exhibited moderate (less than 60%) sequence identity other ring-hydroxylating dioxygenases. PhdC showed features [3Fe-4S] or [4Fe-4S] type [2Fe-2S] that has been in most reported PhdD also 40%) known reductases. phdABCD expressed poorly Escherichia coli even when placed under control strong promoters. introduction Shine-Dalgarno upstream each initiation codon improved their expression E. coli. cells carrying phdBCD phdACD no phenanthrene-degrading activity, those phdABD phdABC activity significantly less genes. It thus concluded all are necessary efficient activity. genetic organization phylogenetically diverged positions these an unusual component suggest be new class aromatic