Targeted metagenomics: finding rare tryptophan dimer natural products in the environment.
Targeted metagenomics: finding rare tryptophan dimer natural products in the environment.
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DOI：
10.1021/jacs.5b01968
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发表时间：
2015-05-13
影响因子：
15
通讯作者：
Brady SF
中科院分区：
文献类型：
--
作者：
Chang FY;Ternei MA;Calle PY;Brady SF
从环境基因组中发现天然产物（宏基因组学）在很大程度上限于筛选现有的环境DNA（eDNA）文库。在这里，我们已经耦合的chromopyrrollic酸合酶（CPAS）基因多样性的化学电泳调查与有针对性的eDNA文库生产，以更有效地访问罕见的色氨酸二聚体（TD）生物合成基因簇。使用eDNA衍生的基因簇的传统和基于合成生物学的异源表达努力的组合导致了两种生物活性TD--羟基孢菌素（1）和还原孢菌素（2）的产生。正如我们对CPAS基因的系统发育分析所表明的，在我们对粗cDNA提取物的调查中鉴定的，还原孢菌素（2）含有前所未有的TD核心结构：吡咯啉吲哚并咔唑核心，这可能是其不寻常的生物活性特征的关键。这项工作证明了使用靶向宏基因组学发现结构罕见和生物学上有趣的天然产物的潜力，其中环境样品被预先筛选以鉴定最具遗传学独特性的基因序列，并且通过靶向宏基因组文库构建和异源表达来访问与这些基因相关的分子。
Natural product discovery from environmental genomes (metagenomics) has largely been limited to the screening of existing environmental DNA (eDNA) libraries. Here, we have coupled a chemical-biogeographic survey of chromopyrrolic acid synthase (CPAS) gene diversity with targeted eDNA library production to more efficiently access rare tryptophan dimer (TD) biosynthetic gene clusters. A combination of traditional and synthetic biology-based heterologous expression efforts using eDNA-derived gene clusters led to the production of hydroxysporine (1) and reductasporine (2), two bioactive TDs. As suggested by our phylogenetic analysis of CPAS genes, identified in our survey of crude eDNA extracts, reductasporine (2) contains an unprecedented TD core structure: a pyrrolinium indolocarbazole core that is likely key to its unusual bioactivity profile. This work demonstrates the potential for the discovery of structurally rare and biologically interesting natural products using targeted metagenomics, where environmental samples are prescreened to identify the most phylogenetically unique gene sequences and molecules associated with these genes are accessed through targeted metagenomic library construction and heterologous expression.