海洋真菌新颖倍半萜环化酶催化机制和相关倍半萜分子合成生物学研究

海洋真菌来源倍半萜是一类具有丰富结构多样性（超过200种骨架）和重要生物活性的天然产物，但各类倍半萜骨架的生物合成机制和合成生物学研究却严重滞后。项目组前期从海洋真菌中发现了四类不同骨架的新颖倍半萜分子（香柠檬烯型和菖蒲烷型倍半萜；苯基螺环补身烷型和苯基螺环新型杂萜），它们的生物合成研究未见报道。本项目将围绕这四类倍半萜分子，开展：① 相关倍半萜环化酶（STC）蛋白结构和催化机制研究，通过结构生物学和体外表征等手段阐明四种倍半萜骨架的形成机制；② 倍半萜分子骨架的合成生物学研究，基于生物合成途径，构建高效生产四类倍半萜骨架的基因工程菌株；③ STC蛋白工程改造研究，基于蛋白结构对STC活性中心及周围关键氨基酸残基定点突变，提高和改变其催化功能，增加倍半萜结构骨架的多样性。本研究旨在引领对STC的理性设计和定向改造研究，开辟对新型倍半萜分子的绿色制备途径，促进对海洋真菌药用资源的有效利用。

Sesquiterpenoids from marine fungi are natural products with rich structural diversity (more than 200 skeletons) and important biological activities, however, the research on the biosynthetic mechanism and synthetic biology of various sesquiterpene skeletons is seriously lagging behind. Sesquiterpenoids with four types of different skeletons were found from four marine fungi in the early stage of the project, including bergamotene-type sesquiterpenoids, acorene-type sesquiterpenoids, phenylspirodrimane-type meroterpenoids, new phenylspiro-type meroterpenoids. The biosynthesis of the four type of different sesquiterpnene skeletons have not been reported, this project will carry out the following research: ① to study the synthetic biology of sesquiterpene skeletons basing on the biosynthetic pathway of sesquiterpenes, construct genetically engineered strains for efficient production of four kinds of sesquiterpene skeletons; ② to solve the crystal structures of STCs and clarify their catalytic mechanisms in combination with the in vitro characterizations of STCs ; ③ to carry out STC protein engineering，improve and change the catalytic functions of STCs by making mutations on important amino acids within the active centers of each STC structures, also increase the diversity of sesquiterpene skeletons. This study will lead the research frontier on rational design and directional modification of STCs, push forward the directed and large-scale green preparation for sesquiterpenoids, promote the effective utilization of marine microbial medicinal resources.