Biochemical and genetic basis of oligocyclic aromatic polyketide formation in basidiomycetes

担子菌中寡环芳香族聚酮化合物形成的生化和遗传基础

• 批准号: 413891605
• 负责人: Professor Dr. Dirk Hoffmeister
• 金额: --
• 依托单位: Lehrstuhl für Pharmazeutische Mikrobiologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2018
• 资助国家: 德国
• 起止时间: 2017-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/413891605?language=en
• 关键词: Biochemical; genetic; basis; oligocyclic; aromatic

Regarding structural diversity and their useful or toxic bioactivities, the polyketides are an outstanding group of natural products. They are produced by polyketide synthases (PKSs), i.e. complex, multifunctional Enzymes. The genetic and biochemical basis of polyketide biosynthesis in bacteria and ascomycetes is well understood. Conversely, the knowledge for basidiomycetes (mushroom-type fungi) is very scarce. The formation of oligocyclic polyketides (e.g. pigments and toxins with this structural feature) in them has remained completely uninvestigated. This knowledge gap is even more surprising, as the basidiomycetes represent a phylum of some 40,000 species and an abundant source of bioactive natural products.The genus Cortinarius (Webcap Mushroom) is one of the largest genera of the basidiomycetes. Species within this genus produce numerous oligocyclic polyketides. Using the Fragrant Webcap (Cortinarius odorifer) as a model, the applicant investigated its genome. This mushroom produces phlegmacins A1 and B1, which are dimeric, methylated oligocyclic polyketides. Six highly similar genes (pks1-pks6) were identified which encode PKSs of a hitherto unknown, evolutionarily separate group. It is hypothesized that these genes/enzymes control the formation of oligocyclic polyketides. This hypothesis is supported by adjacent genes for two methyl transferases and an aromatic peroxidase that may catalyze methylation and dimerization during phlegmacin biosynthesis.This project aims at functional characterization of the enzymes PKS1-PKS6 to test the above hypothesis. To reach this goal, the enzymes will be produced heterologously in a fungal host (Aspergillus niger), followed by product formation in vivo and in vitro. The products will be analyzed by liquid chromatography, mass spectrometry, and nuclear magnetic resonance spectroscopy. In addition, the two methyl transferases will be produced heterologously and characterized. The successfully completed project has model character and lays the foundation for future work to generally understand how structural diversity of toxic or pharmaceutically relevant basidiomycete polyketides is generated.

就结构多样性及其有用或有毒的生物活性而言，聚酮化合物是一组杰出的天然产物。它们由聚酮酶（PKS），即复杂的多功能酶产生。细菌和子囊菌中聚酮化合物生物合成的遗传和生物化学基础已被充分理解。相反，对担子菌（蘑菇型真菌）的认识非常缺乏。其中寡环聚酮化合物（例如具有这种结构特征的色素和毒素）的形成仍然完全未被研究。这种知识空白更令人惊讶，因为担子菌代表了约40，000种的门和生物活性天然产物的丰富来源。Cortinarius（Webcap Mushroom）属是担子菌中最大的属之一。该属内的物种产生许多寡环聚酮化合物。申请人使用芳香Webcap（Cortinarius odelier）作为模型，研究了其基因组。这种蘑菇产生双链菌素A1和B1，它们是二聚的、甲基化的寡环聚酮。六个高度相似的基因（PKS 1-PKS 6）被确定为编码PKSs的一个迄今为止未知的，进化上独立的组。假设这些基因/酶控制寡环聚酮化合物的形成。这一假设得到了两个甲基转移酶和一个芳香族过氧化物酶的相邻基因的支持，这两个酶可能催化在Escherimacin生物合成过程中的甲基化和二聚化。为了达到这一目标，酶将在真菌宿主（尼日尔曲霉）中异源产生，然后在体内和体外形成产物。将通过液相色谱法、质谱法和核磁共振光谱法分析产物。此外，这两种甲基转移酶将异源产生并表征。成功完成的项目具有模型特征，并为今后的工作奠定了基础，以普遍了解有毒或药学相关的担子菌聚酮化合物的结构多样性是如何产生的。