CYCLOHEXANECARBOXYLIC ACID AND POLYKETIDE BIOSYNTHESIS

描述(申请人提供)细菌聚酮生物合成方法 提供广泛的结构多样化的生物活性天然产品，用于 免疫抑制剂、抗生素、抗寄生虫药、生长促进剂和 抗癌剂。遗传学和生物化学研究的巨大进展 与此相关的聚酮合成酶(PKS)及其相关酶 生物合成过程开启了药物发现的新纪元 可以组合或改变工艺的不同组件，以便 获取新的天然产品。对独特的酶的理解，它 两者都提供了在这些过程中使用的不同寻常的生物合成前体，以及 将它们整合到聚酮产品中对这一努力至关重要。这样的一个 在辅酶A被激活的转氨酶生物合成中发现了一个例子 环己烷羧酸(CHC-CoA)是由莽草酸途径生成的 中间体，并随后用于生成最终的抗真菌聚酮 产品。五种抗菌素CHC-CoA生物合成基因的结合 胶状链霉菌与阿维菌素的生物合成基因簇 在Vermitilis宿主链霉菌中的生物合成基因导致了 生产商业新型抗寄生虫剂的工程菌 多拉菌素(一种使用CHC-CoA作为生物合成物产生的阿维菌素类似物 前身)。除了抗寄生虫和抗真菌药物外，CHC-CoA和 相关化合物是用于一组生物合成的重要前体 有望抗肿瘤的聚酮衍生蛋白磷酸酶II抑制剂 抗菌剂以及新型官能化抗菌剂。 这项应用的长期目标是使用CHC-CoA生物合成 基因和一种混合组合生物合成方法产生和 最终测试每一个新成员的生物活性 不同的药物类别。这一目标将通过四个方面来实现 明确的目标。1)CHC-CoA中限速步骤的确定 酶的生物合成和生化特性 路径。 2)生物合成途径基因的克隆和测序 CHC-CoA衍生的抗肿瘤重要成员--磷酸乳霉素 蛋白磷酸酶II抑制剂。3)新一代抗寄生虫和 利用磷乳霉素和CHC-CoA生物合成基因的抗菌药物 作为生成含有杂交聚酮合成酶的细菌宿主的工具 CHC-CoA途径的中间体。4)新型蛋白磷酸酶II的产生 抑制剂，通过操纵和组合生物合成 磷乳霉素生物合成基因簇。

DESCRIPTION (provided by applicant) Bacterial polyketide biosynthetic processes provide a wide range of structurally diverse bioactive natural products used as immunosuppressants, antibiotics, antiparasitics, growth promotants, and anticancer agents. Tremendous advances in genetic and biochemical understanding of the polyketide synthases (PKSs) and related enzymes involved in these biosynthetic processes has ushered in a new era of drug discovery in which different components of the processes can be combined or altered in order to access novel natural products. An understanding of the unique enzymes, which both provide the unusual biosynthetic precursors used in these processes, and incorporate them into a polyketide product is critical to this effort. One such example is found in ansatriemn biosynthesis where coenzyme A activated cyclohexanecarboxylic acid (CHC-CoA) is generated from a shikimate pathway intermediate, and subsequently used to generate the final antifungal polyketide product. Combining five CHC-CoA biosynthetic genes from the ansatrienin biosynthesis gene cluster of Streptomyces collznus with the avermectin biosynthetic genes in an Streptomyces a vermitilis host, has resulted in an engineered strain that produces the commercial novel antiparastic agent doramectin (an avermectin analog generated using CHC-CoA as a biosynthetic precursor). In addition to antiparasitic and antifungal agents, CHC-CoA and related compounds are important precursors used in the biosynthesis of a group of polyketide-derived protein phosphatase II inhibitors, promising antitumor agents, as well as novel functionalized antibacterial agents. The long-term objective of this application is to use the CHC-CoA biosynthetic genes and a hybrid combinatorial biosynthetic approach to generate and ultimately test the biological activity of novel members of each of these different drug classes. This objective will be accomplished through four specific aims. 1) Determination of the rate-limiting step in CHC-CoA biosynthesis and biochemical characterization of the enzymes involved in the pathway. 2) Cloning and sequencing of the biosynthetic pathway genes for formation of CHC-CoA-derived phoslactomycins, members of the important class of antitumor protein phosphatase II inhibitors. 3) Generation of new antiparasitic and antibacterial agents by using the phoslactomycin and CHC-CoA biosynthetic genes as tools to generate bacterial hosts containing hybrid polyketide synthases and CHC-CoA pathway intermediates. 4) Generation of novel protein phosphatase II inhibitors, by manipulation and combinatorial biosynthesis of the phoslactomycin biosynthetic gene cluster.