earticle

영어

During the past decade, aromatic dioxygenases isolated from various bacterial strains have increasingly attracted research interests primarily due to the potential application as biocatalysts for regioselective and enantioselective synthesis of vicinal cis-dihydrodiols (1). As a representative example, the toluene dioxygenase from Pseudomonas putida 39D has been extensively used to produce synthons for chemoenzymatic synthesis (2). Rhodococcus sp. strain DK17 can metabolize various benzene derivatives including o-xylene, toluene, ethylbenzene, and indan by degrading them through a common pathway initiated by a common aromatic oxygenase (3-6). The DK17 oxygenase enzyme possesses the unique ability to perform distinct regioselective hydroxylations that depend on the position and the size of the substituent groups on the aromatic ring. For example, the enzyme catalyzes dioxygenation on the aromatic ring of o-xylene to produce the o-xylene cis-3,4-dihydrodiol form of dihydrodiol or on ethylbenzene to produce the two dihydrodiols, ethylbenzene cis-2,3- and cis-3,4-dihydrodiol. The same enzyme has also been reported to oxidize m-xylene into 3-methylbenzylalcohol and 2,4-dimethylphenol at a ratio of 9:1. This presentation reports on the structure-based engineering and the potential application of the aromatic oxygenase in industrial biocatalysis.