Yunfeng Luo, Xiaoli Ma, Yufan Qiu, Yun Lu, Siyu Shen, Yang Li, Haiyun Gao, Kang Chen, Jiawei Zhou, Tianyuan Hu, Lichan Tu, Huan Zhao, Dan Li, Faqiang Leng, Wei Gao, Tao Jiang, Changli Liu, Luqi Huang, Ruibo Wu, Yuru Tong
The oxidosqualene cyclase (OSC) catalyzed cyclization of the linear substrate (3S)-2,3-oxidosqualene to diverse pentacyclic triterpenoid (PT) skeletons is one of the most complex reactions in nature. Friedelin has a unique PT skeleton involving a fascinating nine-step Cation Shuttle-Run (CSR) cascade arrangement reaction, in which the carbocation formed from C-2 moves to the other side of the skeleton, runs back to C-3 to yield a friedelin cation, and finally deprotonated. However, as the data on the crystal structure of plant OSCs are lacking, it remains unknown why the CSR cascade reactions for friedelin biosynthesis and the exact catalytic mechanism of the CSR...
October 15, 2023: Angewandte Chemie