CLONING AND SEQUENCING OF THE GENE-CLUSTER ENCODING 2 SUBUNITS OF MEMBRANE-BOUND ALCOHOL-DEHYDROGENASE FROM ACETOBACTER-POLYOXOGENES

The membrane-bound alcohol dehydrogenase (ADH) from Acetobacter polyoxogenes NBI1028 is composed of a 72 kDa subunit and a 44 kDa cytochrome c subunit. The amino acid sequences of the two regions of the 72 kDa subunit were determined to prepare oligonucleotides for the purpose of amplification of a DNA fragment corresponding to the intermediate region by the polymerase chain reaction. A 0.5 kb DNA fragment thus amplified was used as the probe to clone a 7.0 kb Pst I fragment coding for the whole 72 kDa subunit. Nucleotide sequencing and immunoblot analysis revealed that the cloned fragment contained the full structural genes for the 72 kDa and the 44 kDa subunits and they were clustered with the same transcription polarity. The predicted amino acid sequence of the gene for the 72 kDa subunit showed homology with that of the 72 kDa subunit from ADH of A. aceti and those of methanol dehydrogenase from methylotrophic bacteria. The 72 and 44 kDa subunits contained one and three typical haem binding sequences, respectively.