A novel angular dioxygenase gene cluster encoding 3-phenoxybenzoate 1',2'-dioxygenase in Sphingobium wenxiniae JZ-1.

摘要: Sphingobium wenxiniae JZ-1 utilizes a wide range of pyrethroids and their metabolic product, 3-phenoxybenzoate, as sources carbon energy. A mutant strain, MJZ-1, defective in the degradation 3-phenoxybenzoate was obtained by successive streaking on LB agar. Comparison draft genomes strains MJZ-1 revealed that 29,366-bp DNA fragment containing putative angular dioxygenase gene cluster (pbaA1A2B) is missing strain MJZ-1. PbaA1, PbaA2, PbaB share 65%, 52%, 10% identity with corresponding α β subunits ferredoxin component dioxin from Sphingomonas wittichii RW1, respectively. Complementation pbaA1A2B resulted active 1′,2′-dioxygenase, but enzyme activity Escherichia coli achieved only through coexpression glutathione reductase (GR)-type gene, pbaC, indicating 1′,2′-dioxygenase belongs to type IV Rieske non-heme iron aromatic ring-hydroxylating oxygenase system consisting hetero-oligomeric oxygenase, [2Fe-2S]-type ferredoxin, GR-type reductase. The pbaC not located immediate vicinity pbaA1A2B. 3-Phenoxybenzoate catalyzes hydroxylation 1′ 2′ positions benzene moiety yielding 3-hydroxybenzoate catechol. Transcription induced transcriptional level far less than pbaA1A2B, implying possibility PbaC may be can physiologically transfer electrons PbaA1A2B JZ-1. Some reductases other sphingomonad could also PbaA1A2B, suggesting has low specificity for