基于基因组采掘和合成生物学技术的海洋放线菌中活性大环内酯类化合物的定向发掘

海洋放线菌是活性天然产物发现的重要资源，但传统模式下获得化合物的盲目性较高，化合物重复发现严重。因此，如何定向发掘菌株的代谢潜能，准确地获得有价值的活性化合物，成为海洋微生物资源开发利用过程中急需解决的问题。申请人拟联合运用基因组定向采掘技术和组合生物合成新技术，聚焦大环内酯类结构，探索从海洋放线菌中定向发现活性化合物的新方法。申请人前期基于大环内酯的生物合成规律，设计了新型特异性基因探针，从课题组海洋放线菌资源库中成功筛选获得了具有目标化合物产生能力的菌株，并得到了一个结构新颖的大环内酯类化合物 hindamycin A，对耐药菌表现出了明显的抑制活性。基于此，申请人将继续应用基因组定向采掘技术发掘海洋放线菌中新型大环内酯类天然产物；并针对 hindamycin A 的结构，运用组合生物合成技术对其结构进行改造，探讨构效关系，以期获得新型药物先导化合物，为海洋创新药物的研究提供基础。

Marine actinomycetes are important resources for the discovery of bioactive natural products. While along with more and more bioactive compounds discovered from marine actinomycetes, scientists frequently meet the problem that a big amount of compounds are being repeatedly isolated and characterized. Therefore, how to directly explore the metabolic potential of strains and accurately obtain valuable active compounds has become an urgent problem to be solved in the development and utilization of marine microbial resources. With this purpose, we will utilize a combination of PCR-directed genome mining techniques and combinatorial biosynthesis technologies, to discover type I polyketide derived macrolides from marine-derived actinomycetes. In a pilot work, we have designed a degenerated PCR primer as a DNA probe which specially target the genes responsible for type I polyketide pathway associated macrolides biosynthesis. By using this probe, a deep-sea derived Streptomyces strain with macrolides producing potency was obtained and as a result of the following chemical study, a macrolide hindamycin A was obtained, which showed obvious antibacterial activity against several clinical drug-resistant strains. Based on the above findings, we will continue to use the PCR-directed genomic mining technology to discover new macrolide products from marine actinomycetes; and for a further step on the yet obtained structure hindamycin A, we will employ heterologous expression and combinatorial biosynthesis techniques to produce diversified structures for the structure-activity study. Through above efforts, we want to develop a new method for bringing up pharmaceutical compounds from the ocean and promote the basic research of marine innovative drugs.