Chemoenzymatic analysis of bryostatin biosynthesis

性状（由申请方提供）：苔藓抑素是从海洋苔藓虫Bugula neritina中分离的聚酮化合物次级代谢产物。苔藓抑素1是一种非常有前途的抗癌药物，目前正在进行II期临床试验。不幸的是，B. Neritina的含量非常低，迄今为止，没有化学合成替代品，需要收获大量动物以获得足够数量的苔藓抑素用于生物测试。最近的研究表明，苔藓抑素是由细菌内共生体，Endobugula sertula产生的，但试图培养微生物并不成功。因此，最新的研究工作已经导致在鉴定的聚酮合酶（PKS）基因簇共生丰富的DMA，可能是负责苔藓抑素生物合成。然而，由于生物体不能培养，因此不能进行可以验证该簇是否产生苔藓抑素的突变和互补实验。在这个项目中，我建议使用纯化的推定苔藓抑素PKS模块的体外研究，以确定是否这个基因簇实际上是负责生产苔藓抑素。这项研究可能导致异源宿主产生苔藓抑素。

DESCRIPTION (provided by applicant): Bryostatins are polyketide secondary metabolites isolated from the marine bryozoan Bugula neritina. Bryostatin 1 is a very promising anti-cancer drug, and is currently undergoing Phase II clinical trials. Unfortunately, bryostatin concentrations in B. neritina are very low and, to date, there are no chemical synthetic alternatives, requiring the harvest of large amounts of the animal to obtain sufficient quantities of bryostatin for biotesting. Recent research has revealed that the bryostatins are produced by the bacterial endosymbiont, Endobugula sertula, but attempts to culture the microbe have not been successful. Consequently, the latest research effort has resulted in the identification of a polyketide synthase (PKS) gene cluster from symbiont-enriched DMA that may be responsible for bryostatin biosynthesis. However, as the organism cannot be cultured, mutation and complementation experiments that can verify whether this cluster produces bryostatin cannot be conducted. In this project, I propose to use in vitro studies with purified putative bryostatin PKS modules to determine whether this gene cluster is in fact responsible for the production of bryostatin. This research may lead to production of bryostatin by a heterologous host.