Nucleotide sequencing and transcriptional mapping of the genes encoding biphenyl dioxygenase, a multicomponent polychlorinated-biphenyl-degrading enzyme in Pseudomonas strain LB400.

AUTOR(ES)

Erickson, B D

RESUMO

The DNA region encoding biphenyl dioxygenase, the first enzyme in the biphenyl-polychlorinated biphenyl degradation pathway of Pseudomonas species strain LB400, was sequenced. Six open reading frames were identified, four of which are homologous to the components of toluene dioxygenase from Pseudomonas putida F1 and have been named bphA, bphE, bphF, and bphG. From this comparison, biphenyl dioxygenase was found to be a multicomponent enzyme containing a two-subunit iron-sulfur protein, a ferredoxin, and a reductase. Comparison of the large subunit of the iron-sulfur protein and the ferredoxin with other multicomponent dioxygenases identified amino acid sequences similar to Rieske iron-sulfur proteins for binding a [2Fe-2S] cluster. Sequences have also been identified in the reductase component that match the consensus sequence for FAD or NAD binding. Transcription of the biphenyl dioxygenase region was examined, and three transcription initiation sites were identified. Transcription initiating at the site furthest upstream is greatly increased when the LB400 cells are grown on biphenyl as the sole carbon source.

Documentos Relacionados

• Induction of bphA, Encoding Biphenyl Dioxygenase, in Two Polychlorinated Biphenyl-Degrading Bacteria, Psychrotolerant Pseudomonas Strain Cam-1 and Mesophilic Burkholderia Strain LB400
• Oxidation of biphenyl by a multicomponent enzyme system from Pseudomonas sp. strain LB400.
• Cloning and expression in Escherichia coli of Pseudomonas strain LB400 genes encoding polychlorinated biphenyl degradation.
• Purification and characterization of the oxygenase component of biphenyl 2,3-dioxygenase from Pseudomonas sp. strain LB400.
• Dihydroxylation and dechlorination of chlorinated biphenyls by purified biphenyl 2,3-dioxygenase from Pseudomonas sp. strain LB400.