Actinomadura hibisca mutant with distrupted O- methyltransferase gene of pradimicin and preparing of demethylpradimicin using the same

摘要

A mutant of Actinomadura hibisca is provided to produce only demethylpradimicin as a new antifungal antibiotic of pradimicin having a new structure by ruining an O-methyltransferase gene of pradimicin associated with methylation. A method for producing an Actinomadura hibisca mutant BC1(KACC 95057P) producing demethylpradimicin represented by the formula(2) comprises the steps of: (1) preparing a genomic DNA library of Actinomadura hibisca by using a cosmid vector, and obtaining a cosmid clone containing a pradimicin biosynthesis gene group; (2) inserting an antibiotic-resistant gene into an O-methyltransferase gene DNA fragment in the pradimicin A biosynthesis gene group to prepare a knock-out cassette; (3) integrating the knock-out cassette into the DNA fragment containing the pradimicin biosynthesis gene group to prepare a knock-out vector; and (4) introducing the knock-out vector into Actinomadura hibisca through conjugation, and transforming Actinomadura hibisca through homologous recombination to knock-out the O-methyltransferase gene.