Tunicamycin,a potent reversible translocase I inhibitor,is produced by several Actinomycetes species.The tunicamycin structure is highly unusual,and contains an 11-carbon dialdose sugar and anα,β-1″,11′-glycosidic...Tunicamycin,a potent reversible translocase I inhibitor,is produced by several Actinomycetes species.The tunicamycin structure is highly unusual,and contains an 11-carbon dialdose sugar and anα,β-1″,11′-glycosidic linkage.Here we report the identification of a gene cluster essential for tunicamycin biosynthesis by high-throughput heterologous expression(HHE)strategy combined with a bioassay.Introduction of the genes into heterologous non-producing Streptomyces hosts results in production of tunicamycin by these strains,demonstrating the role of the genes for the biosynthesis of tunicamycins.Gene disruption experiments coupled with bioinformatic analysis revealed that the tunicamycin gene cluster is minimally composed of 12 genes(tunA–tunL).Amongst these is a putative radical SAM enzyme(Tun B)with a potentially unique role in biosynthetic carbon-carbon bond formation.Hence,a seven-step novel pathway is proposed for tunicamycin biosynthesis.Moreover,two gene clusters for the potential biosynthesis of tunicamycin-like antibiotics were also identified in Streptomyces clavuligerus ATCC 27064 and Actinosynnema mirums DSM 43827.These data provide clarification of the novel mechanisms for tunicamycin biosynthesis,and for the generation of new-designer tunicamycin analogs with selective/enhanced bioactivity via combinatorial biosynthesis strategies.展开更多
基金This work was supported by the National Basic Research Program(973 Program)the National Programs for High Technology Research Development Program(863 Program)from the Ministry of Science and Technology,the National Science Foundation of China,the Ministry of Education,the Science and Technology Commission of Shanghai Municipality,and Shanghai Leading Academic Discipline Project B203.
文摘Tunicamycin,a potent reversible translocase I inhibitor,is produced by several Actinomycetes species.The tunicamycin structure is highly unusual,and contains an 11-carbon dialdose sugar and anα,β-1″,11′-glycosidic linkage.Here we report the identification of a gene cluster essential for tunicamycin biosynthesis by high-throughput heterologous expression(HHE)strategy combined with a bioassay.Introduction of the genes into heterologous non-producing Streptomyces hosts results in production of tunicamycin by these strains,demonstrating the role of the genes for the biosynthesis of tunicamycins.Gene disruption experiments coupled with bioinformatic analysis revealed that the tunicamycin gene cluster is minimally composed of 12 genes(tunA–tunL).Amongst these is a putative radical SAM enzyme(Tun B)with a potentially unique role in biosynthetic carbon-carbon bond formation.Hence,a seven-step novel pathway is proposed for tunicamycin biosynthesis.Moreover,two gene clusters for the potential biosynthesis of tunicamycin-like antibiotics were also identified in Streptomyces clavuligerus ATCC 27064 and Actinosynnema mirums DSM 43827.These data provide clarification of the novel mechanisms for tunicamycin biosynthesis,and for the generation of new-designer tunicamycin analogs with selective/enhanced bioactivity via combinatorial biosynthesis strategies.
