Metabolic Engineering of Yeast for Polyketide Production

描述(申请人提供)：聚酮是一组不同的 具有重要临床意义的天然产物。通向高位的主要障碍 天然和基因工程聚酮的水平生产已经 缺乏(A)在功能上表达的一般异源系统 聚酮合酶和辅酶和(B)含有足够的水平 酰基辅酶A底物。这个项目的长期目标是 聚酮优化酿酒酵母菌株的构建 生产过剩。 在第一阶段，我们发现在极低的温度下可以产生真菌聚酮。 在酿酒酵母中含量较高。我们还证明了这三个基因 红霉素聚酮前体的功能表达 在异源链霉菌宿主中分离出质粒。 在计划的第二阶段，我们会： (A)培养酵母宿主菌株，以(I)产生底物和 产生模块化多酮所需的翻译后酶；(Ii)具有 必要的营养缺乏，以允许积极选择至少 三个相容的质粒；以及(Iii)将允许放射性标记-CoA 池子和聚酮合成酶。 (B)证明该菌株可以表达模块化聚酮合成酶 并在适合商业开发的水平上生产复杂的聚酮。 建议的商业应用： 一种普通的高产酵母菌株将使商业生产成为可能 有价值的多酮，与现有的本地产品相比，显著节省了成本和时间 寄主生物体和生产方法。

DESCRIPTION (provided by applicant): The polyketides are a diverse group of natural products with great clinical importance. A major barrier to the high level production of both natural and genetically engineered polyketides has been the lack of a generic heterologous system that (a) functionally expresses the polyketide synthase and accessory enzymes and (b) contains adequate levels of acyl-Coenzyme A substrates. The long term goal of this project is to construct strains of Saccharomyces cerevisiae optimized for polyketide overproduction. In Phase I, we showed that a fungal polyketide could be produced at extremely high levels in S. cerevisiae. We also demonstrated that the three genes for the polyketide precursor of erythromycin could be functionally expressed from separate plasmids in a heterologous Streptomyces host. In Phase II of the project we will: (a) Develop yeast host strains that (i) produce substrates and post-translational enzymes necessary to produce modular polyketides; (ii) have necessary nutritional deficiencies to allow positive selection of at least three compatible plasmids; and (iii) will permit radioactive labeling of -CoA pools and polyketide synthases. (b) Demonstrate that such a strain can express a modular polyketide synthase and produce a complex polyketide at levels suitable for commercial development. PROPOSED COMMERCIAL APPLICATION: A generic overproducing yeast strain will enable production of commercially valuable polyketides with significant cost and time savings over existing native host organisms and production methods.