真菌新颖聚酮herpotrichones的生物合成机制研究

微生物聚酮类天然产物具有独特的化学结构和良好的生物活性，是药物研发的重要源泉，同时为新颖酶学机理和新生物合成机制的研究提供了很好的研究材料。Herpotrichones A和B是真菌来源具有抗神经炎活性的新骨架芳香聚酮类天然产物，其生物合成机制尚不清楚。本项目已完成目标菌株的全基因组测序，并建立了遗传操作体系，通过生物信息学分析预测了可能的生物合成基因簇。在此基础上，我们拟通过基因敲除确定herpotrichones完整的生物合成基因簇；综合中间体分离鉴定、异源表达和体外酶功能验证等技术手段挖掘和研究簇中的新功能基因，对催化两个生物合成基因簇偶联的分子间[4+2]环加成反应酶及催化傅克酰基化反应酶的机理进行研究，从基因及酶催化反应的角度理解其生物合成过程。本项目进一步说明了两个或多个基因簇的互作增加了天然产物结构的多样性，对新颖酶催化机制的发现和新型药源分子的挖掘具有借鉴意义。

Polyketide natural products isolated from microbes usually have unique and complicated chemical structures, which provide excellent research materials for discovering the enzymes with interesting catalytic mechanisms and mining the unprecedented biosynthetic pathways. Herpotrichones A and B are aromatic polyketides with new skeleton. They are derived from fungi and display anti-neuroinflammatory activity. However, its biosynthetic mechanism has not been investigated. To address it, we have completed the whole genome sequence of the target strain, established the genetic manipulation system, and analyzed the possible biosynthetic gene clusters by bioinformatics. Based on these researches, we try to carry out the following studies: (1) identification of the complete biosynthetic gene cluster of herpotrichones through gene knockout; (2) investigation of the mechanism of the intermolecular Diels-Alderase that catalyzes the coupling of two separate biosynthetic gene clusters as well as the enzyme that catalyzes the Friedel-Crafts acylation reaction.This project further illustrates that the interaction of two or more biosynthetic gene clusters increases the structural diversity of natural products, and is of great significance for the discovery of enzymes with novel catalytic mechanisms as well as the bioactive molecules.