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Cloning and Heterologous Expression of Three Type II PKS Gene Clusters from Streptomyces bottropensis
Author(s) -
Yan Xiaohui,
Probst Katharina,
Linnenbrink Anton,
Arnold Moritz,
Paululat Thomas,
Zeeck Axel,
Bechthold Andreas
Publication year - 2012
Publication title -
chembiochem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.05
H-Index - 126
eISSN - 1439-7633
pISSN - 1439-4227
DOI - 10.1002/cbic.201100574
Subject(s) - streptomyces albus , gene cluster , cosmid , heterologous expression , streptomyces , biosynthesis , biology , polyketide , heterologous , biochemistry , gene , genetics , bacteria , recombinant dna
Abstract Mensacarcin is a potent cytotoxic agent isolated from Streptomyces bottropensis. It possesses a high content of oxygen atoms and two epoxide groups, and shows cytostatic and cytotoxic activity comparable to that of doxorubicin, a widely used drug for antitumor therapy. Another natural compound, rishirilide A, was also isolated from the fermentation broth of S. bottropensis . Screening a cosmid library of S. bottropensis with minimal PKS‐gene‐specific primers revealed the presence of three different type II polyketide synthase (PKS) gene clusters in this strain: the msn cluster (mensacarcin biosynthesis), the rsl cluster (rishirilide biosynthesis), and the mec cluster (putative spore pigment biosynthesis). Interestingly, luciferase‐like oxygenases, which are very rare in Streptomyces species, are enriched in both the msn cluster and the rsl cluster. Three cosmids, cos2 (containing the major part of the msn cluster), cos3 (harboring the mec cluster), and cos4 (spanning probably the whole rsl cluster) were introduced into the general heterologous host Streptomyces albus by intergeneric conjugation. Expression of cos2 and cos4 in S. albus led to the production of didesmethylmensacarcin (DDMM, a precursor of mensacarcin) and the production of rishirilide A and B (a precursor of rishirilide A), respectively. However, no product was detected from the expression of cos3. In addition, based on the results of isotope‐feeding experiments in S. bottropensis , a putative biosynthesis pathway for mensacarcin is proposed.