Copyright C) 1992, American Society for Microbiology Cloning, Expression, and Sequence Analysis of the Bacillus

The gene (mdh) coding for methanol dehydrogenase (MDH) of thermotolerant, methylotroph Bacils mehunolicus Cl has been cloned and sequenced. The deduced amino acid sequence of the mdh gene exhibited similarity to those of five other alcohol dehydrogenase (type IE) enzymes, which are distinct from the long-chain zinc-containing (type I) or short-chain zinc-lacking (type II) enzymes. Highly efficent expression of the udh gene in Escerichia chdi was probably driven from its own promoter sequence. After purfcation of MDH from E. coli, the kinetic and biochemical properties of the enzyme were ivestiged. The physiological effect of MDH synthesis in E. coli and the role of conserved sequence patterns in type m alcohol dehydrogenases have been analyzed and are discussed. Bacillus methanolicus Cl is a representative of the ther-motolerant methanol-utilizing Bacillus spp. which oxidize methanol by use of an NAD-dependent methanol dehydro-genase (MDH) (3, 5, 9). The previously reported N-terminal amino acid sequence (27) has shown that the enzyme belongs to a novel family of NAD-dependent alcohol dehydrogena-ses (ADHs) which includes Zymomonas mobilis ADH2 (8)