The biphenyl/polychlorinated biphenyl-degradation locus (bph) of Pseudomonas sp. LB400 encodes four additional metabolic enzymes.

摘要: Abstract The bph locus of Pseudomonas sp. LB400, encoding biphenyl/polychlorinated biphenyl (PCB) degradation, contains a region about 3.5 kb hitherto unknown function, between bphC and bphD. This DNA segment has now been characterized. Four structural genes have located identified by combination expression cloning, enzyme activity tests sequencing. four closely spaced cistrons (bphKHJI) glutathione S-transferase (GST), 2-hydroxypenta-2,4-dienoate hydratase, an acetaldehyde dehydrogenase (acylating) 4-hydroxy-2-oxovalerate aldolase, respectively. latter three are enzymes required for conversion the aliphatic end product bphABCD-encoded catabolism biphenyls to Krebs cycle intermediates. discovery these provides rationale growth strain on chlorinated which yield benzoates as dead-end metabolites. sequences involved 54–71% identical those homologous encoded dmp xyl operons. role GST in degradation is less clear, but since it was found contain, putative xenobiotic substrate-binding domain, shares 29% amino acids with bacterial tetrachlorohydroquinone dehalogenase, may be dehalogenation PCB-degradative