文献类型：期刊文献

英文题名：G2 Helix as the Plastic Region Modulating Diastereoselectivity of Cyclization in Fungal Bifunctional Sesterterpene Synthases

作者：Zhang, Weiyan[1];Xu, Kangwei[2];Lan, Keying[1];Xu, Wujue[1];Peng, Kaitong[1];Lv, Kangjie[1];Zhang, Yanye[1];Zhang, Jingyu[1];Nie, Shaoping[3];Jiang, Yi[4];Hsiang, Tom[5];Zhang, Lixin[1];Wu, Ruibo[2];Liu, Xueting[1]

机构：[1]East China Univ Sci & Technol, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[2]Sun Yat Sen Univ, Sch Pharmaceut Sci, Guangzhou 510006, Peoples R China;[3]Nanchang Univ, State Key Lab Food Sci & Resources, Nanchang 330031, Peoples R China;[4]Yunnan Univ, Yunnan Inst Microbiol, Key Lab Res & Dev Actinomycete Resources, Chenggong Dist, Kunming 650500, Peoples R China;[5]Univ Guelph, Sch Environm Sci, Guelph, ON N1G 2W1, Canada

年份：2025

卷号：15

期号：15

起止页码：12984

外文期刊名：ACS CATALYSIS

收录：;EI(收录号：20253318984540);WOS:【SCI-EXPANDED(收录号:WOS:001530034000001)】；

基金：This work was supported by the National Natural Science Foundation of China (21977029 and 32121005), Shanghai Sci-Tech Inno Center for Infection & Immunity (SSIII-2024A01 and SSIII-2024A02), the National Key Research and Development Program of China (2019YFA0906200 and 2022YFC2105400), the National Major Scientific Instruments and Equipment Development Project of the National Natural Science Foundation of China (32327801), the Shanghai Municipal Science and Technology Major Project, The 111 Project (B18022), and the Science and Technology Commission of Shanghai Municipality (21NL2600100). I would also like to express my gratitude to my cat, Tiantian, for her constant companionship.

语种：英文

外文关键词：G2 helix; fungal sesterterpenesynthase; diastereoselectivity; mutagenesis; conformational flexibility

摘要：Sesterterpenoids are a rare class of terpenes with potential pharmaceutical applications. To date, most of the currently characterized fungal sesterterpenoids are produced through the catalysis of bifunctional sesterterpene synthases (BF-STPSs). However, the full catalytic potential of BF-STPSs is not yet fully understood. Here, using site-directed mutagenesis and computational simulations, we identified the G2 helix of BF-STPSs as a structurally plastic region that governs divergent cyclization pathways, leading to the formation of unique terpenes with distinct diastereoselectivity. Mutations in the functional site residues of the G2 helix in Type A BF-STPSs, DpPS and FoFS, altered the conformational flexibility of the carbocation intermediates, yielding a series of previously uncharacterized sesterterpenes with unprecedented diastereoselectivity in B-ring cyclization via a selective attack on the diastereotopic faces of the olefin. Notably, FoFS-V195A catalyzed the formation of five different skeleton types, while DpPS-V194A represented a rare example of a protein-engineered switch from a bicyclic to a tricyclic skeleton with a Z-configured Delta 11,12 double bond. Density functional theory (DFT) calculations and molecular dynamics (MD) simulations provided further insights into the reaction details and active site dynamics. These findings highlight key amino acids within the G2 helix of BF-STPSs as mutational hotspots, providing an efficient strategy to accelerate the discovery of structurally diverse sesterterpenes.