RT Journal Article SR Electronic(1) A1 Han, Lei A1 Yang, Keqian A1 Ramalingam, Eswar A1 Mosher, Roy H. A1 Vining, Leo C.YR 1994 T1 Cloning and characterization of polyketide synthase genes for jadomycin B biosynthesis in Streptomyces venezuelaeISP5230 JF Microbiology, VO 140 IS 12 SP 3379 OP 3389 DO https://doi.org/10.1099/13500872-140-12-3379 PB Microbiology Society, SN 1465-2080, AB Hybridizing fragments in the genomic DNA of Streptomyces venezuelaeISP5230, which produces the jadomycin group of angucycline antibiotics, were detected by probing with actlDNA from Streptomyces coelicolorA3(2). The hybridizing regions were isolated from a 16.5 kb insert of S. venezuelae DNA recovered from a genomic library cloned in aλ replacement vector. Subcloning and sequencing of a 4.8 kb segment of the insert, containing regions hybridizing to actIIIas well as actl, identified five open reading frames (ORFs). The deduced polypeptide products of the ORFs closely resemble in sequence the components of streptomycete type-II polyketide synthases (PKSs): the ORF1 product corresponds to the ketoacyl synthase, and the ORF2 product to a polypeptide closely related to the ketoacyl synthase and involved in determining chain length; the ORF3 product matches the acyl carrier protein; ORF4 encodes a bifunctional cyclase/dehydrase; and ORF5 encodes a ketoreductase. Integration into the chromosomal DNA of a plasmid containing a segment of the ORF2-ORF4 region severely depressed jadomycin B biosynthesis; since the integrant showed no change in growth or spore pigmentation, the cloned PKS genes are presumed to encode enzymes in the pathway for jadomycin biosynthesis., UL https://www.microbiologyresearch.org/content/journal/micro/10.1099/13500872-140-12-3379