CLONING AND NUCLEOTIDE-SEQUENCE OF A BACTERIAL CYTOCHROME P-450(VD25) GENE ENCODING VITAMIN-D-3 25-HYDROXYLASE

The gene encoding an enzyme that catalyzes the hydroxylation at position 25 of vitamin D-3 was cloned from an actinomycete strain, Amycolata autotrophica, by use of a host-vector system of Streptomyces lividans. The amino acid sequence deduced from the nucleotide sequence revealed that this enzyme, tentatively named P-450(VD25), contains several regions of strong similarity with amino acid sequences of cytochromes P-450 from a variety of organisms, primarily in the regions of an oxygen-binding site and a heme ligand pocket. Especially, P-450(VD25) shows end-to-end similarity in amino acid sequence to P-450(dNIR) of Fusarium oxysporum and P-450(SU2) of Streptomyces griseolus. The recombinant S. lividans strain containing the P-450(VD25) gene on a multicopy plasmid converted vitamin D-3 in the medium into 25-hydroxyvitamin D-3 at a maximum yield of 10%.