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Identification and characterization of a novel CprA reductive dehalogenase specific to highly chlorinated phenols from Desulfitobacterium hafniense strain PCP-1

Bisaillon, Ariane; Beaudet, Réjean; Lépine, François; Déziel, Éric; Villemur, Richard (2010). Identification and characterization of a novel CprA reductive dehalogenase specific to highly chlorinated phenols from Desulfitobacterium hafniense strain PCP-1 Applied and Environmental Microbiology , vol. 76 , nº 22. p. 7536-7540. DOI: 10.1128/AEM.01362-10.

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Résumé

Desulfitobacterium hafniense strain PCP-1 reductively dechlorinates pentachlorophenol (PCP) to 3-chlorophenol and a variety of halogenated arom. compds. at the ortho, meta, and para positions. Several reductive dehalogenases (RDases) are thought to be involved in this cascade of dehalogenation. We partially purified a novel RDase involved in the dechlorination of highly chlorinated phenols from strain PCP-1 cultivated in the presence of 2,4,6-trichlorophenol. The RDase was membrane assocd., and the activity was sensitive to oxygen, with a half-life of 128 min upon exposure to air. The pH and temp. optima were 7.0 and 55°C, resp. Several highly chlorinated phenols were dechlorinated at the ortho positions. The highest dechlorinating activity levels were obsd. with PCP, 2,3,4,5-tetrachlorophenol, and 2,3,4-trichlorophenol. 3-Chloro-4-hydroxyphenylacetate, 3-chloro-4-hydroxybenzoate, dichlorophenols, and monochlorophenols were not dechlorinated. The apparent Km value for PCP was 46.7 μM at a Me viologen concn. of 2 mM. A mixt. of iodopropane and titanium citrate caused a light-reversible inhibition of the dechlorinating activity, suggesting the involvement of a corrinoid cofactor. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the partially purified prepn. revealed 2 bands with apparent mol. masses of 42 and 47 kDa. Mass spectrometry anal. using Mascot to search the genome sequence of D. hafniense strain DCB-2 identified the 42-kDa band as NADH-quinone oxidoreductase, subunit D, and the 47-kDa band as the putative chlorophenol RDase CprA3. This is the first report of an RDase with high affinity and high dechlorinating activity toward PCP

Type de document:
Mots-clés libres: DEHALOSPIRILLUM-MULTIVORANS, FRAPPIERI PCP-1, DEHALOCOCCOIDES-ETHENOGENES, MOLECULAR CHARACTERIZATION, DEHALOBACTER-RESTRICTUS, PCE-S, TETRACHLOROETHENE, PURIFICATION, DECHLORINATION, ENZYME
Centre: Centre INRS-Institut Armand Frappier
Date de dépôt: 30 avr. 2014 18:48
Dernière modification: 30 avr. 2014 18:48
URI: http://espace.inrs.ca/id/eprint/2214

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