真菌中蕴藏着丰富的结构新颖和具有显著生物活性的天然产物，非常适合于新药和先导化合物的发现。真菌NRPS生物合成途径通过CT功能域催化控制产物释放和大环环合反应，与细菌来源的TE功能域不同的是，CT功能域需要结合特异性的T功能域后才能进行催化反应。本项目拟与美国加州洛杉矶分校的唐奕教授展开合作，希望能够解析出三环肽生物碱fumiquinazoline F生物合成途径中的TqaA-CT和六环肽天然产物棘白菌素B生物合成途径中的EcdA-CT的晶体结构，同时测定出TqaA-CT/TqaA-T复合物和TqaA-CT/小分子抑制剂复合物的晶体结构，结合突变体测活、分子动力学计算等手段揭示出真菌生物合成途径非核糖体肽合成酶中CT催化线性肽酰前体的释放和大环环化反应的分子机理。通过本项目实施，将会在分子水平上帮助我们深入理解细菌和真菌生物合成机制的差异，也可以为促进真菌组合生物合成提供良好的理论基础。

There are many natural products with novel chemical structures and obvious biochemical activities in fungi, which enables it very suitable for discovering new drugs or lead compounds. The NRPS biosynthetic pathway in fungi uses a condensation-like (CT) domain to control the product release and macrocyclization reaction. In contrast to the thioesterase (TE) domain in bacteria, the CT domain need to tether to the natural T-domain for efficient catalysis. We aim to solve the crystal structures of TqaA-CT in fumiqunazoline F biosynthesis and EcdA-CT in echinocandin B biosynthesis by collaboration with Professor Yi Tang at UCLA. We also plan to determine the complex structures of TqaA-CT/TqaA-T and TqaA with its inhibitors. We hope to combine the structural information, mutagenesis data, and molecular dynamics caculations to elucidate the molecular mechanism of how the fungal CT domain catalyzed the reaction of linear peptidyl precusor release and macrocyclization. Understanding the role of the CT domain in fungal NRPS will not only broaden our knowledge in bacterial and fungi biosynthesis, but also provide essential information for promoting fugi combinatorial biosynthesis.