Development of PKS biocatalysts on the example of a multi-enzyme cascade for improved synthesis of antifungal polyketides

该项目旨在推动建立聚酮合成酶(PKS)模块作为生物催化剂，并展示其在天然产物全合成中的优势。例如，将开发一个多酶级联，其中心是来自Ambrticin生物合成的PKS模块Ambmod4。对条件进行量身定做的调整应该能够使模块与其他酶组分进行最佳相互作用。这一级联反应将在化学酶法全合成Jerangolide方面找到具体的应用。在那里，它旨在用有效的一锅法取代多步骤、合成困难的乙烯基四氢吡喃的形成，从而显著缩短最长的线性序列。为了建立酶的级联反应，将对Ambmod4的生产进行优化，并将确定合适的硫酯酶结构域，该结构域选择性地释放所需的Ambmod4产物，同时避免可想象的副反应。这将使与Ambmod4的制备生物催化反应成为可能。这一级联反应将通过C-甲基转移酶和环化酶逐步扩展，并扩大到半制备规模。

This project aims to advance the establishment of polyketide synthase (PKS) modules as biocatalysts and to demonstrate the advantages of their use in the total synthesis of natural products. As an example, a multi-enzyme cascade is to be developed, with the PKS module AmbMod4 from the ambruticin biosynthesis at its centre. A tailor-made adaptation of the conditions should enable an optimal interaction of the module with the other enzymatic components. This cascade will find a concrete application in the context of the chemoenzymatic total synthesis of jerangolides. There, it is intended to replace the multi-step, synthetically difficult formation of a vinyltetrahydropyran by an efficient one-pot process, thereby significantly shortening the longest linear sequence. In order to establish the enzyme cascade, the production of AmbMod4 will be optimized and a suitable thioesterase domain will be identified which selectively releases the desired AmbMod4 product while avoiding conceivable side reactions. This would enable preparative biocatalytic reactions with AmbMod4. This cascade is to be gradually extended by a C-methyltransferase and a cyclase and scaled up to the semi-preparative scale.