[Cloning of genes coding for 3-alpha-hydroxysteroid dehydrogenase and for (3-17)-beta-hydroxysteroid dehydrogenase...

A genomic library of Pseudomonas testosteroi total DNA constructed from SauIIIA digests ligated to a lambda gt11 vector was probed with different polyclonal antibodies raised against purified 3 alpha-HSD and (3 beta-17 beta)-HSD. Two different clones reacting with one antibody were selected. The clone reacting with (3-17)beta-HSD antibody contained a 2,661-base pair insert and was found to contained an open reading frame of 765 base pair that corresponds to a protein of 254 amino-acid residues. A 1,492-base pair was inserte in pBR 322 plasmid vector; the recombinant bacterie over expressed the (3-17)beta-HSD gene. The clone reacting with 3 alpha-HSD antibody contained a 1746 base pair insert which contained an open reading frame of 696 base pairs that corresponds to a protein of 231 amino-acid residues. A search for homologous proteins was performed. Distant similarities were found between (3-17)beta-HSD and members of the short-chain alcool dehydrogenase (SCAD) family but no similarity was observed between 3 alpha-HSD and proteins of this family.