基于深海链霉菌SCSIO 03032基因组信息挖掘新结构次级代谢产物

In the past decade, marine actinomycetes have been documented as a significant resource for producing novel secondary metabotites of leads for drug discovery, as many novel metabotites with anti-infective and antitumor activities have been identified from such organisms. Particularly, many of these were obtained from new genera or species of marine actinomycetes. The strain Streptomyces sp. SCSIO 03032 was isolated from a sediment sample (E 87 59.70, N 9 59.30) at a depth of 3412 m from the Bay of Bengal in the Indian Ocean and it was identified as a new species on the basis of its 16S rRNA gene sequence. Four new bisindole alkaloids spiroindimicins A-D and three polyketide macrolactams heronamides D-F were obtained from the fermentation broth of Streptomyces sp. SCSIO 03032 in our previous work. Further to evaluate the biosynthetic potential of this strain, the whole genome (6,243,587-bp) of SCSIO 03032 has been sequenced and all identifiable secondary metabolism gene clusters were analyzed. Genome analysis revealed 26 secondary metabolic biosynthesis gene clusters in complete genome sequence. Based on these data, we intend to use the method of genome mining to discover new natural products from the strain SCSIO 03032. Genome sequencing based mining as new strategies are powerful model can be employed for discovering new natural products. Numberours of novel natural products were discovered from sequenced microbes by genomics-guided approaches. In this current project, we intend to use one strain many compounds method (OSMAC), feeding with isotope-labelled precursors, heterologous expression, activation of silent gene clusters, and functional gene knockout, coupled with the analysis methods of HPLC-DAD-UV、LC-MS to discover new secondary metabolites from the strain Streptomyces sp. SCSIO 03032. Natural products and their derivatives form the basis of many important drugs that have found wide spread use in the clinic and new secondary metabolites obtained from SCSIO 03032 may form the basis for new drug leads. Besides, the structure of the novel compound bears a novel enzymatic mechanism. The project also provides a new basis for microbiologists to study the enzymatic mechanism, and provide inspiration of organic synthesis of small molecular compounds for organic chemists.

Streptomyces sp. SCSIO 03032是从深海沉积物中分离得到的链霉菌属新种，基因组测序结果表明它含有编码多种类型次级代谢产物的生物合成基因簇。前期研究中,我们从中分离到结构新颖的双吲哚螺环生物碱spiroindimicins A-D及大环内酰胺heronamides D-F。鉴于Streptomyces sp. SCSIO 03032蕴藏着巨大的次级代谢产物合成能力，本项目拟以生物信息学分析为指导，采用OSMAC、同位素示踪、异源表达、调控基因调节、功能基因敲除等生物学手段，结合HPLC-DAD-UV、LC-MS的化学分析、排重方法，对该菌株的次级代谢产物进行深度挖掘，以期获得结构新颖的天然产物，为微生物药物提供先导化合物。同时，结构新颖的化合物蕴藏着新颖的酶学机制，本项目也为研究新的酶学机制提供基础，为合成新的小分子化合物提供灵感。

Streptomyces sp. SCSIO 03032 是从深海沉积物中分离得到的链霉菌属新种，基因组测序结果表明它含有编码多种类型次级代谢产物的生物合成基因簇。我们从中分离到结构新颖的双吲哚螺环生物碱spiroindimicins A-D 及大环内酰胺heronamides D-F。在生物学信息的指导下，我们采用OSMAC的方法，发现了芳酰胺类化合物，通过氧化酶基因缺失发现了heronamides的结构类似物，通过卤化酶、甲基转移酶功能缺失、异源表达等方法发现了新的 indimicins结构类似物，共获得26个化合物，其中17个为新化合物，2个新化合物具有较好的细胞毒活性，新化合物发现丰富了天然产物结构类型；以分离获得的化合物为基础，结合同位素标记，基因敲除，初步解析两种类型化合物生物合成机制。以上完成的研究内容已发表SCI论文3篇，中文核心期刊1篇。申请专利2项，另有1篇文章正在整理。培养博士研究生1名。