Plasmid-mediated degradation of 4-chloronitrobenzene by newly isolated Pseudomonas putida strain ZWL73.
A strain of Pseudomonas putida ZWL73 was isolated from soil contaminated with chloronitrobenzenes and identified by 16S rDNA sequencing. This bacterium released chloride and ammonia into the medium when grown on 4-chloronitrobenzene (4CNB) as the sole source of carbon, nitrogen and energy. A plasmid designated pZWL73 of approximately 100 kb in this strain was found to be responsible for 4CNB degradation. This was based on the fact that the plasmid-cured strains showed 4CNB- phenotype and the 4CNB+ phenotype could be conjugally transferred. The cell-free extracts of strain ZWL73 exhibited chloronitrobenzene nitroreductase and 2-amino-5-chlorophenol 1, 6-dioxygenase (2A5CPDO) activities, but neither activity was found from that of the plasmid-cured strain. We have also cloned a 4.9-kb EcoRI fragment exhibiting 2A5CPDO activity. Sequencing results revealed beta-subunit (cnbCa) and alpha subunit (cnbCb) of a meta-cleavage dioxygenase, which were subsequently expressed in E. coli with 2A5CPDO activity. The phylogenetic analysis suggested that 2A5CPDO may form a new subgroup in class III meta-cleavage dioxygenase with its close homologs.
Zhen
Da
D
Wuhan Institute of Virology, Chinese Academy of Science, Wuhan 430071, People's Republic of China.
Liu
Hong
H
Wang
Shu-Jun
SJ
Zhang
Jun-Jie
JJ
Zhao
Fei
F
Zhou
Ning-Yi
NY
D001673:Biodegradation, Environmental; D049308:Dioxygenases / Q000235:genetics* / Q000378:metabolism*; D009578:Nitrobenzenes / Q000378:metabolism*; D010957:Plasmids / Q000235:genetics; D016958:Pseudomonas putida / Q000235:genetics* / Q000378:metabolism*
D009578:Nitrobenzenes; C010407:4-chloronitrobenzene; D049308:Dioxygenases