Biosynthesis and Enzymology of Antifungal Natural Products

摘要 高感染频率、高死亡率、出现耐药性、 为数不多的治疗选择和耗尽的发现渠道导致迫切需要找到 新的抗真菌分子。天然产物，尤指由真菌种类产生的天然抗真菌产品 武器，已经并将继续发挥重要作用，并为药物发现提供线索。实现 天然产物作为抗真菌先导化合物的巨大潜力，以及发现新结构的前景 通过基因组引导的方法，我们正在提出一个全面的、多学科的项目来研究 真菌衍生的2-吡啶酮生物碱的生物合成，这是一种复杂的天然产物，具有强大的 选择性抗真菌活性。我们将特别关注一组不同的酶催化的周环 产生对生物活性很重要的多环支架的反应。发现了这些酶， 随后对机制和序列-活性关系进行详细研究，将改善我们的 对酶催化的基本了解，并使生物合成工程方法能够 天然产物类似物，并扩大新抗真菌药物的基因组挖掘线索。这一多PI提案带来了 天然产物研究的三个方面的互补专业知识：生物合成、计算 化学和合成。我们将共同解决三个目标：1)研究SAM依赖的周周期蛋白 勒波林作为一个典范系统。2)研究吡哆醇生物合成中的Alder-ene反应和脱苯基反应； 3)含十氢林抗真菌2-吡啶酮类化合物的生物合成研究。洞察世界 这些分子的生物合成将揭示对催化周环反应的酶的基本见解， 并为结构导向的天然产物发现提供线索。

ABSTRACT The combination of high frequencies of infection, high mortality rates, emergence of drug resistance, small number of therapeutic options and a depleted discovery pipeline has resulted in an urgent need for finding new antifungal molecules. Natural products, especially those produced by fungal species as natural antifungal weapons, have been and will continue to play important roles and provide leads for drug discovery. Realizing the immense potential of natural products as antifungal leads, and the prospects of discovering new structures through genome-guided methods, we are proposing a comprehensive and multidisciplinary project to investigate the biosynthesis of fungal-derived 2-pyridone alkaloids, which are complex natural products with potent and selective antifungal activities. We will be particularly focused on a diverse set of enzyme-catalyzed pericyclic reactions that give rise to the polycyclic scaffold important for biological activity. Uncovering these enzymes, followed by detailed investigation of the mechanisms and sequence-activity relationships, will improve our fundamental understanding of enzyme catalysis, and enable biosynthetic engineering approaches to generate natural product analogs, and expand genome mining leads for new antifungals. This multi-PI proposal bring together complementary expertise in three aspects of natural product research: biosynthesis, computational chemistry and synthesis. Together we will address three aims: 1) Investigate SAM-dependent pericyclase using leporin as a model system. 2) Investigate Alder-Ene and dephenylation reactions in pyridoxatin biosynthesis; and 3) Investigate biosynthesis of decalin-containing antifungal 2-pyridone compounds. Insights into the biosynthesis of these molecules will reveal fundamental insights into enzymes that catalyze pericyclic reactions, and provide leads for structure-guided natural product discovery.