Distribution of oxoacyl synthase homology sequences within Streptomyces DNA

A genomic DNA sequence of Streptomyces strain ISP 5485 was cloned, sequenced and compared with corresponding information from nuclei acid data banks. The DNA sequence was unique, but showed homology to DNA coding for the condensing enzyme, 2-oxoacyl synthase, of the deoxyerythronolide B synthase complex (DEBS) from Saccharopolyspora erythraea NRRL 2338. A subfragment of the sequenced DNA was used to construct a gene-specific probe that formed part of the putative 2-oxoacyl synthase gene. The PCR-amplified and labelled probe was used in hybridization experiments involving 33 streptomycete strains that produced different classes of antibiotics. The probe showed widespread homology with DNA considered to be part of analogous genes within genomes of different polyketide producers. The implications of the probe homology to bacterial chromosomal DNA are discussed.