Cloning and characterization of a polyketide synthase gene from Streptomyces fradiae Tü2717, which carries the genes for biosynthesis of the angucycline antibiotic urdamycin A and a gene probably involved in its oxygenation

Abstract

A DNA fragment was cloned as cosmid purd8, which encodes a polyketide synthase involved in the production of the angucycline antibiotic urdamycin from Streptomyces fradiae Tü2717. Deletion of the polyketide synthase genes from the chromosome abolished urdamycin production. In addition, purd8 conferred urdamycin resistance on introduction into Streptomyces lividans TK24. Sequence analysis of 5.7 kb of purd8 revealed six open reading frames transcribed in the same direction. The deduced amino acid sequences of the six open reading frames strongly resemble proteins from known type II polyketide synthase gene clusters: a ketoacyl synthase, a chain length factor, an acyl carrier protein, a ketoreductase, a cyclase, and an oxygenase. Heterologous expression of the urdamycin genes encoding a ketoacyl synthase and a chain length factor in Streptomyces glaucescens tetracenomycin C-nonproducing mutants impaired in either the TcmK ketoacyl synthase or TcmL chain length factor resulted in the production of tetracenomycin C. Heterologous expression of a putative oxygenase gene from the urdamycin gene cluster in S. glaucescens GLA.O caused production of the hybrid antibiotic 6-hydroxy tetracenomycin C.

Cloning and heterologous expression of the entire gene clusters for PD 116740 from Streptomyces strain WP 4669 and tetrangulol and tetrangomycin from Streptomyces rimosus NRRL 3016

“…The genes for the latter product are not expressed during actinorhodin production (48). We have also found two apparent PKS clusters in the kinamycin producer Streptomyces murayamaensis (20), and the urdamycin producer Streptomyces fradiae Tü 2717 also contains two (8). It is possible that the unexpressed clusters from S. rimosus NRRL 3016 and WP 4669 may code for spore pigments.…”

“…However, in only some cases has heterologous production of a complete pathway been obtained (18,30,37,38), while in a number of cases the product of the reported PKS genes is entirely unknown (25). During the course of our studies, cloning of portions of gene clusters for two other angucyclinones has been reported, as evidenced by gene disruption experiments (8,19). Our strategy has been to clone fragments of DNA large enough to maximize the likelihood of obtaining heterologous production of the target metabolites as a means of unequivocally confirming the identity of the genes.…”

Functional Angucycline-Like Antibiotic Gene Cluster in the Terminal Inverted Repeats of the Streptomyces ambofaciens Linear Chromosome

“…1) is identical to that seen for their homologues involved in the biosynthesis of the angucycline antibiotics jadomycin (jadIABCED) (20,26), urdamycin (urdFABCDL) (12,16), landomycin (lanFABCDL) (50), and kinamycin (the proposed kinIABCED locus; accession number AY228175).…”

Identification of the Function of Gene lndM2 Encoding a Bifunctional Oxygenase-Reductase Involved in the Biosynthesis of the Antitumor Antibiotic Landomycin E by Streptomyces globisporus 1912 Supports the Originally Assigned Structure for Landomycinone

“…1 Previous sequence alignment studies revealed two other putative oxygenase-encoding genes to be present in both landomycin gene clusters, namely, lanE/lndE and lanM/lndM. [3][4][5]14 The similarity of lanE (and therefore also lndE) with urdE [14][15][16] suggested that this gene is most likely involved in the generation of the p-quinone moiety. Therefore, the putative oxygenases LanM/LndM were the best candidates for being responsible for the 6-oxygenation in landomycin biosynthesis.…”