Open AccessDuplication of a 2,4-dichlorophenoxyacetic acid monooxygenase gene in Alcaligenes eutrophus JMP134(pJP4)
Author(s) -
Edward J. Perkins,
Paul F. Lurquin
Publication year - 1988
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.170.12.5669-5672.1988
Subject(s) - biology , subcloning , plasmid , gene , locus (genetics) , alcaligenes , microbiology and biotechnology , escherichia coli , monooxygenase , genetics , restriction map , enzyme , biochemistry , bacteria , pseudomonas , cytochrome p450
The Alcaligenes eutrophus JMP134 plasmid pJP4 contains genes necessary for the complete degradation of 2,4-dichlorophenoxyacetic acid (2,4-D) and 3-chlorobenzoic acid. tfdA encodes 2,4-D monooxygenase, the initial enzyme in the 2,4-D catabolic pathway. The tfdA locus has recently been localized to a region on pJP4 13 kilobases away from a cluster of five genes, tfdB to tfdF, which encode the enzymes responsible for the further degradation of 2,4-D to chloromaleylacetic acid (W.R. Streber, K. N. Timmis, and M. H. Zenk, J. Bacteriol. 169:2950-2955, 1987). A second, dissimilar locus on pJP4, tfdAII, has been observed which encodes 2,4-D monooxygenase activity. Gas chromatographic analysis of the 2,4-D metabolites of A. eutrophus harboring pJP4 or subclones thereof localized tfdAII to within a 9-kilobase SstI fragment of pJP4 which also carries the genes tfdBCDEF. This fragment was further characterized in Escherichia coli by deletion and subcloning analysis. A region of 2.5 kilobases, adjacent to tfdC, enabled E. coli extracts to degrade 2,4-D to 2,4-dichlorophenol. Hybridization under low-stringency conditions was observed between tfdA and tfdAII, signifying that the 2,4-D monooxygenase gene was present as two related copies on pJP4.