T. Tobimatsu et al., MOLECULAR-CLONING, SEQUENCING, AND EXPRESSION OF THE GENES ENCODING ADENOSYLCOBALAMIN-DEPENDENT DIOL DEHYDRASE OF KLEBSIELLA-OXYTOCA, The Journal of biological chemistry, 270(13), 1995, pp. 7142-7148
The pdd genes encoding adenosylcobalamin-dependent diol dehydrase of K
lebsiella oxytoca were cloned by using a synthetic oligodeoxyribonucle
otide as a hybridization probe followed by measuring the enzyme activi
ty of each clone. Five clones of Escherichia coli exhibited diol dehyd
rase activity. At least one of them was shown to express diol dehydras
e genes under control of their own promoter, Sequence analysis of the
DNA fragments found in common in the inserts of these five clones and
the flanking regions revealed four open reading frames separated by 10
-18 base pairs. The sequential three open reading frames from the seco
nd to the fourth (pddA, pddB, and pddC genes) encoded polypeptides of
554, 224, and 173 amino acid residues with predicted molecular weights
of 60,348 (alpha), 24,113 (beta), and 19,173 (gamma), respectively, O
verexpression of these three genes in E. coli produced more than 50 fo
ld higher level of functional apodiol dehydrase than that in K. oxytoc
a. The recombinant enzyme was indistinguishable from the wild-type one
of R. oxytoca by the criteria of polyacrylamide gel electrophoretic a
nd immunochemical properties. It was thus concluded that these three g
ene products are the subunits of functional diol dehydrase. Comparison
s of the deduced amino acid sequences of the three subunits with other
proteins failed to reveal any apparent homology.