A flavin reductase stimulates DszA and DszC proteins of Rhodococcus erythropolis IGTS8 in vitro

Rhodococcus erythropolis IGTS8 is a gram positive bacterium, which can catabolize dibenzothiophene to 2-hydroxybiphenyl and inorganic sulfur without the cleavage of carbon-carbon bonds. Three structural genes, dszA, dszB, and dszC, have been cloned and shown to be necessary for this phenotype. Here, we demonstrate that a FMN:NADPH oxidoreductase from Vibrio harveyi complements activities of purified DszA and DszC proteins. Furthermore, we propose that DszA and DszC are oxygenase units that do not use NAD(P)H directly, but instead use FMNH2 from a FMN:NADPH oxidoreductase for oxygenation.