Functional expression of three Rieske non-heme iron oxygenases derived from actinomycetes in Rhodococcus species for investigation of their degradation capabilities of dibenzofuran and chlorinated dioxins.
The activity of Rieske non-heme iron oxygenases (aromatic hydrocarbon dioxygenases, AhDOs) is important for the bacterial degradation of aromatic pollutants such as polycyclic aromatic hydrocarbons and dioxins. During our analysis of the role of AhDOs in dioxin bioremediation, some enzymes derived from high G + C Gram-positive actinomycetes were difficult to produce in active form in the Escherichia coli protein expression system. In this study, we constructed a heterologous expression system for AhDOs in Rhodococcus species using a constitutive expression promoter, P(dfdB), and a shuttle vector, pRK401, and analyzed the ability of these enzymes to degrade dibenzofuran and deplete several chlorinated dioxins. Three active AhDOs expressed in Rhodococcus strains that were difficult to obtain by the E. coli system showed different regiospecificities for dibenzofuran bioconversion as well as different substrate depletion specificities for chlorinated dioxins. Moreover, AhDO derived from R. erythropolis TA421 showed relatively diverse depletion-substrate specificity for chlorinated dioxins.
Ecomolecular Biorecycling Science Research Team, RIKEN Advanced Science Institute, Wako, Saitama 351-0198, Japan. tiida@jcm.riken.jp
Toshiya
T
Iida
Yasuhiro
Y
Moteki
Kaoru
K
Nakamura
Katsuhiko
K
Taguchi
Masato
M
Otagiri
Miwako
M
Asanuma
Naoshi
N
Dohmae
Ron
R
Usami
Toshiaki
T
Kudo
D000192:Actinomycetales / Q000201:enzymology*; D001426:Bacterial Proteins / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism; D001572:Benzofurans / Q000302:isolation & purification / Q000378:metabolism*; D001673:Biodegradation, Environmental; D003001:Cloning, Molecular; D004147:Dioxins / Q000302:isolation & purification / Q000378:metabolism*; D049308:Dioxygenases / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism*; D004785:Environmental Pollutants / Q000302:isolation & purification / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D012240:Rhodococcus / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D001572:Benzofurans; D004147:Dioxins; D004785:Environmental Pollutants; C023614:dibenzofuran; D049308:Dioxygenases