Metabolic Engineering of Yeast for Polyketide Production

描述（由申请人提供）：聚酮化合物是一组不同的化合物， 具有重要临床意义的天然产物。一个主要的障碍， 天然和基因工程聚酮化合物的水平生产 一直缺乏一个通用的异源系统，（a）功能性表达 聚酮合酶和辅助酶，以及（B）含有足够水平的 酰基辅酶A底物。该项目的长期目标是 聚酮化合物优化的酿酒酵母构建菌株 生产过剩。 在第一阶段，我们发现真菌聚酮化合物可以在极低的温度下产生， 在S.啤酒。我们还证明了三个基因， 红霉素的聚酮前体可以从 分离异源链霉菌宿主中的质粒。 在项目的第二阶段，我们将： (a)开发酵母宿主菌株，（i）产生底物， 产生模块化聚酮化合物所必需的翻译后酶;（ii）具有 必要的营养缺乏，以允许积极选择至少 三种相容的质粒;和（iii）将允许-CoA的放射性标记 池和聚酮酶。 (b)证明这样的菌株可以表达模块化聚酮化合物合酶 并以适合商业开发的水平生产复合聚酮化合物。 拟定商业应用： 一种通用的高产酵母菌株将使商业生产成为可能。 与现有的天然聚酮化合物相比， 宿主生物和生产方法。

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.