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Xu M, Xu H, Lei Z, Xing B, Dickschat JS, Yang D, Ma M. Structural Insights Into the Terpene Cyclization Domains of Two Fungal Sesterterpene Synthases and Enzymatic Engineering for Sesterterpene Diversification. Angew Chem Int Ed Engl 2024; 63:e202405140. [PMID: 38584136 DOI: 10.1002/anie.202405140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 04/02/2024] [Accepted: 04/04/2024] [Indexed: 04/09/2024]
Abstract
Little is known about the structures and catalytic mechanisms of sesterterpene synthases (StTSs), which greatly hinders the structure-based engineering of StTSs for structural diversity expansion of sesterterpenes. We here report on the crystal structures of the terpene cyclization (TC) domains of two fungal StTSs: sesterfisherol synthase (NfSS) and sesterbrasiliatriene synthase (PbSS). Both TC structures contain benzyltriethylammonium chloride (BTAC), pyrophosphate (PPi), and magnesium ions (Mg2+), clearly defining the catalytic active sites. A combination of theory and experiments including carbocationic intermediates modeling, site-directed mutagenesis, and isotope labeling provided detailed insights into the structural basis for their catalytic mechanisms. Structure-based engineering of NfSS and PbSS resulted in the formation of 20 sesterterpenes including 13 new compounds and four pairs of epimers with different configurations at C18. These results expand the structural diversity of sesterterpenes and provide important insights for future synthetic biology research.
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Affiliation(s)
- Meng Xu
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Houchao Xu
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany
| | - Zhenyu Lei
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Baiying Xing
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Jeroen S Dickschat
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany
| | - Donghui Yang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
| | - Ming Ma
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, 38 Xueyuan Road, Haidian District, Beijing, 100191, China
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Gu B, Goldfuss B, Dickschat JS. Two Sesterterpene Synthases from Lentzea atacamensis Demonstrate the Role of Conformational Variability in Terpene Biosynthesis. Angew Chem Int Ed Engl 2024; 63:e202401539. [PMID: 38372063 DOI: 10.1002/anie.202401539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Revised: 02/15/2024] [Accepted: 02/16/2024] [Indexed: 02/20/2024]
Abstract
Mining of two multiproduct sesterterpene synthases from Lentzea atacamensis resulted in the identification of the synthases for lentzeadiene (LaLDS) and atacamatriene (LaATS). The main product of LaLDS (lentzeadiene) is a new compound, while one of the side products (lentzeatetraene) is the enantiomer of brassitetraene B and the other side product (sestermobaraene F) is known from a surprisingly distantly related sesterterpene synthase. LaATS produces six new compounds, one of which is the enantiomer of the known sesterterpene Bm1. Notably, for both enzymes the products cannot all be explained from one and the same starting conformation of geranylfarnesyl diphosphate, demonstrating the requirement of conformational flexibility of the substrate in the enzymes' active sites. For lentzeadiene an intriguing thermal [1,5]-sigmatropic rearrangement was discovered, reminiscent of the biosynthesis of vitamin D3. All enzyme reactions and the [1,5]-sigmatropic rearrangement were investigated through isotopic labeling experiments and DFT calculations. The results also emphasize the importance of conformational changes during terpene cyclizations.
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Affiliation(s)
- Binbin Gu
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Bernd Goldfuss
- Department for Chemistry, University of Cologne, Greinstraße 4, 50939, Cologne, Germany
| | - Jeroen S Dickschat
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
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Xu H, Dickschat JS. Isotopic labelings for mechanistic studies. Methods Enzymol 2024; 699:163-186. [PMID: 38942502 DOI: 10.1016/bs.mie.2024.01.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/30/2024]
Abstract
The intricate mechanisms in the biosynthesis of terpenes belong to the most challenging problems in natural product chemistry. Methods to address these problems include the structure-based site-directed mutagenesis of terpene synthases, computational approaches, and isotopic labeling experiments. The latter approach has a long tradition in biosynthesis studies and has recently experienced a revival, after genome sequencing enabled rapid access to biosynthetic genes and enzymes. Today, this allows for a combined approach in which isotopically labeled substrates can be incubated with recombinant terpene synthases. These clearly defined reaction setups can give detailed mechanistic insights into the reactions catalyzed by terpene synthases, and recent developments have substantially deepened our understanding of terpene biosynthesis. This chapter will discuss the state of the art and introduce some of the most important methods that make use of isotopic labelings in mechanistic studies on terpene synthases.
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Affiliation(s)
- Houchao Xu
- Kekulé-Institute for Organic Chemistry and Biochemistry, Rheinische Friedrich-Wilhelms-University of Bonn, Bonn, Germany
| | - Jeroen S Dickschat
- Kekulé-Institute for Organic Chemistry and Biochemistry, Rheinische Friedrich-Wilhelms-University of Bonn, Bonn, Germany.
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Huang ZY, Taizoumbe KA, Liang C, Goldfuss B, Xu JH, Dickschat JS. Spiroluchuene A Synthase: A Cyclase from Aspergillus luchuensis Forming a Spirotetracyclic Diterpene. Angew Chem Int Ed Engl 2023; 62:e202315659. [PMID: 37962519 DOI: 10.1002/anie.202315659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 11/14/2023] [Accepted: 11/14/2023] [Indexed: 11/15/2023]
Abstract
The diterpene synthase AlTS was identified from Aspergillus luchuensis. AlTS catalyses the formation of the diterpene hydrocarbon spiroluchuene A, which exhibits a novel skeleton characterised by a spirocyclic ring system. The cyclisation mechanism towards this compound was elucidated through isotopic labelling experiments in conjunction with DFT calculations and metadynamic simulations. The biosynthetic intermediate luchudiene, besides the derivative spiroluchuene B, was captured from an enzyme variant obtained through site-directed mutagenesis. With its 10-membered ring luchudiene is structurally related to germacrenes and can undergo a Cope rearrangement to luchuelemene.
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Affiliation(s)
- Zheng-Yu Huang
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, East China University of Science and Technology, Shanghai, 200237, China
| | - Kizerbo A Taizoumbe
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Chengqin Liang
- College of Pharmacy, Guilin Medical University, Guilin, 541004, China
| | - Bernd Goldfuss
- Department of Chemistry, University of Cologne, Greinstraße 4, 50939, Cologne, Germany
| | - Jian-He Xu
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, East China University of Science and Technology, Shanghai, 200237, China
| | - Jeroen S Dickschat
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
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Chhalodia AK, Xu H, Tabekoueng GB, Gu B, Taizoumbe KA, Lauterbach L, Dickschat JS. Functional characterisation of twelve terpene synthases from actinobacteria. Beilstein J Org Chem 2023; 19:1386-1398. [PMID: 37736393 PMCID: PMC10509563 DOI: 10.3762/bjoc.19.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2023] [Accepted: 09/04/2023] [Indexed: 09/23/2023] Open
Abstract
Fifteen type I terpene synthase homologs from diverse actinobacteria that were selected based on a phylogenetic analysis of more than 4000 amino acid sequences were investigated for their products. For four enzymes with functions not previously reported from bacterial terpene synthases the products were isolated and their structures were elucidated by NMR spectroscopy, resulting in the discovery of the first terpene synthases for (+)-δ-cadinol and (+)-α-cadinene, besides the first two bacterial (-)-amorpha-4,11-diene synthases. For other terpene synthases with functions reported from bacteria before the products were identified by GC-MS. The characterised enzymes include a new epi-isozizaene synthase with monoterpene synthase side activity, a 7-epi-α-eudesmol synthase that also produces hedycaryol and germacrene A, and four more sesquiterpene synthases that produce mixtures of hedycaryol and germacrene A. Three phylogenetically related enzymes were in one case not expressed and in two cases inactive, suggesting pseudogenisation in the respective branch of the phylogenetic tree. Furthermore, a diterpene synthase for allokutznerene and a sesterterpene synthase for sesterviolene were identified.
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Affiliation(s)
- Anuj K Chhalodia
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Houchao Xu
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Georges B Tabekoueng
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Binbin Gu
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Kizerbo A Taizoumbe
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Lukas Lauterbach
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
| | - Jeroen S Dickschat
- Kekulé-Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany
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