Cloning and characterization of a FAD-monooxygenase gene ( cadA) involved in degradation of chloranilic acid (2,5-dichloro-3,6-dihydroxybenzo-1,4-quinone) in Pseudomonas putida TQ07.
A bacterium culture was isolated on the basis of its ability to degrade chloranilic acid, and was later identified as Pseudomonas putida (TQ07). Several transposon insertion mutants unable to degrade chloranilic acid were selected. The characterization of the site of insertion of one of these mutants led to the identification of the cadA gene encoding an enzyme with significant homology with FAD-monooxygenases involved in the degradation of aromatic and chloroaromatic compounds. The finding that, after replacing the mutant allele with the wild-type one, the strain recovered the wild-type pattern of "halo" formation (a zone of clearing color on agar plates around TQ07 colonies that degrade chloranilic acid) and degradation of chloranilic acid, unequivocally assigned cadA a function in the metabolism of this compound. We also found that most of the transposon insertion mutants unable to degrade chloranilic acid are clustered in a 10-kb region of the P. putidagenome that is encoded in a megaplasmid or in an unstable chromosomal region.
Treviño-Quintanilla
L G
LG
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Postal 510-3, Cuernavaca, Morelos 62251, México.
Galán-Wong
L J
LJ
Rodríguez-Uribe
B
B
Soberón-Chávez
G
G
D000595:Amino Acid Sequence; D016227:Benzoquinones / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003001:Cloning, Molecular; D004251:DNA Transposable Elements; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010105:Oxygenases / Q000235:genetics* / Q000378:metabolism*; D016958:Pseudomonas putida / Q000145:classification / Q000201:enzymology* / Q000235:genetics / Q000254:growth & development; D017422:Sequence Analysis, DNA
D016227:Benzoquinones; D004251:DNA Transposable Elements; D010105:Oxygenases; C020066:dimethylaniline monooxygenase (N-oxide forming); C014400:chloranilic acid