Characterization of the Rhodococcus sp. NI86/21 gene encoding alcohol: N,N'-dimethyl-4-nitrosoaniline oxidoreductase inducible by atrazine and thiocarbamate herbicides.

A protein with a mol.mass of 51,000 (ThcE) that was induced in Rhodococcus sp. NI86/21 during assimilation of thiocarbamate herbicides, atrazine, ethanol, propanol, glycerol, propionaldehyde or ethanolamine was identified by two-dimensional electrophoresis. The thcE gene was cloned and sequenced. The deduced amino acid sequence revealed ThcE as a member of group III alcohol dehydrogenases. ThcE displayed strong homology with sequenced subunit fragments of the homodecameric N,N'-dimethyl-4-nitrosoaniline-dependent alcohol oxidoreductases (MNO) of Amycolatopsis methanolica and Mycobacterium gastri. N-Terminal sequence analysis of purified MNO from Rhodococcus sp. NI86/21 confirmed the identity with ThcE. When overproduced in Escherichia coli, ThcE was insoluble and no MNO activity was detected.