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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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2
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Xu H, Köllner TG, Chen F, Dickschat JS. Functional and Mechanistic Characterization of the 4,5-diepi-Isoishwarane Synthase from the Liverwort Radula lindenbergiana. Chembiochem 2024; 25:e202400104. [PMID: 38372483 DOI: 10.1002/cbic.202400104] [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: 02/01/2024] [Revised: 02/19/2024] [Accepted: 02/19/2024] [Indexed: 02/20/2024]
Abstract
The microbial type sesquiterpene synthase RlMTPSL4 from the liverwort Radula lindenbergiana was investigated for its products, showing the formation of several sesquiterpene hydrocarbons. The main product was structurally characterized as the new compound 4,5-diepi-isoishwarane, while the side products included the known hydrocarbons germacrene A, α-selinene, eremophilene and 4,5-diepi-aristolochene. The cyclization mechanism towards 4,5-diepi-isoishwarane catalyzed by RlMTPSL4 was investigated through isotopic labeling experiments, revealing the stereochemical course for the deprotonation step to the neutral intermediate germacrene A, a reprotonation for its further cyclization, and a 1,2-hydride shift along the cascade. The absolute configuration of 4,5-diepi-isoishwarane was determined using a stereoselective deuteration approach, revealing an absolute configuration typically observed for a microbial type sesquiterpene.
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Affiliation(s)
- Houchao Xu
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
| | - Tobias G Köllner
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745, Jena, Germany
| | - Feng Chen
- Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN, 37996-4561, USA
| | - Jeroen S Dickschat
- Kekulé Institute of Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121, Bonn, Germany
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3
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Xu H, Köllner TG, Chen F, Dickschat JS. Mechanistic characterisation of a sesquiterpene synthase for asterisca-1,6-diene from the liverwort Radula lindenbergiana and implications for pentalenene biosynthesis. Org Biomol Chem 2024; 22:1360-1364. [PMID: 38240688 DOI: 10.1039/d3ob02088f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2024]
Abstract
A sesquiterpene synthase from the liverwort Radula lindenbergiana was characterised and shown to produce the new sesquiterpene hydrocarbon (3R,9R)-asterisca-1,6-diene, besides small amounts of pentalenene. The biosynthesis of asterisca-1,6-diene was studied through isotopic labelling experiments, giving additional insights into the long discussed biosynthesis of pentalenene.
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Affiliation(s)
- Houchao Xu
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.
| | - Tobias G Köllner
- Max Planck Institute for Chemical Ecology, Hans-Knöll-Straße 8, 07745 Jena, Germany
| | - Feng Chen
- Department of Plant Sciences, University of Tennessee, 2431 Joe Johnson Drive, Knoxville, TN 37996-4561, USA
| | - Jeroen S Dickschat
- Kekulé-Institute for Organic Chemistry and Biochemistry, University of Bonn, Gerhard-Domagk-Straße 1, 53121 Bonn, Germany.
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Li H, Dickschat JS. Diterpene Biosynthesis from Geranylgeranyl Diphosphate Analogues with Changed Reactivities Expands Skeletal Diversity. Angew Chem Int Ed Engl 2022; 61:e202211054. [PMID: 36066489 PMCID: PMC9826473 DOI: 10.1002/anie.202211054] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Indexed: 01/11/2023]
Abstract
Two analogues of the diterpene precursor geranylgeranyl diphosphate with shifted double bonds, named iso-GGPP I and iso-GGPP II, were enzymatically converted with twelve diterpene synthases from bacteria, fungi and protists. The changed reactivity in the substrate analogues resulted in the formation of 28 new diterpenes, many of which exhibit novel skeletons.
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Affiliation(s)
- Heng Li
- Kekulé-Institute for Organic Chemistry and BiochemistryUniversity of BonnGerhard-Domagk-Straße 153121BonnGermany
| | - Jeroen S. Dickschat
- Kekulé-Institute for Organic Chemistry and BiochemistryUniversity of BonnGerhard-Domagk-Straße 153121BonnGermany
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5
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Li H, Dickschat JS. Diterpene Biosynthesis from Geranylgeranyl Diphosphate Analogues with Changed Reactivities Expands Skeletal Diversity. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202211054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Heng Li
- University of Bonn: Rheinische Friedrich-Wilhelms-Universitat Bonn Kekulé-Institute for Organic Chemistry and Biochemistry GERMANY
| | - Jeroen S. Dickschat
- University of Bonn: Rheinische Friedrich-Wilhelms-Universitat Bonn Kekulé Institute for Organic Chemistry and Biochemistry Gerhard-Domagk-Straße 1 53121 Bonn GERMANY
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Huang ZY, Wu QY, Li CX, Yu HL, Xu JH. Facile Production of (+)-Aristolochene and (+)-Bicyclogermacrene in Escherichia coli Using Newly Discovered Sesquiterpene Synthases from Penicillium expansum. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:5860-5868. [PMID: 35506591 DOI: 10.1021/acs.jafc.2c01885] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Penicillium expansum, producer of a wide array of secondary metabolites, has the potential to be a source of new terpene synthases. In this work, a platform was constructed with Escherichia coli BL21(DE3) by enhancing its endogenous 2-methyl-d-erythritol-4-phosphate pathway to supply sufficient terpenoid precursors. Using this precursor-supplying platform, we discovered two sesquiterpene synthases from P. expansum: PeTS1, a new (+)-aristolochene synthase, and PeTS4, the first microbial (+)-bicyclogermacrene synthase. To enhance the sesquiterpene production by PeTS1, we employed a MBP fusion tag to improve the heterologous protein expression, resulting in the increase of aristolochene production up to 50 mg/L in a 72 h flask culture, which is the highest production reported to date. We also realized the first biosynthesis of (+)-bicyclogermacrene, achieving 188 mg/L in 72 h. This work highlights the great potential of this microbial platform for the discovery of new terpene synthases and opens new ways for the bioproduction of other valuable terpenoids.
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Affiliation(s)
- Zheng-Yu Huang
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Qing-Yang Wu
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Chun-Xiu Li
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Hui-Lei Yu
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, People's Republic of China
| | - Jian-He Xu
- State Key Laboratory of Bioreactor Engineering, Shanghai Collaborative Innovation Centre for Biomanufacturing, Frontiers Science Center for Materiobiology and Dynamic Chemistry, East China University of Science and Technology, Shanghai 200237, People's Republic of China
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7
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Dickschat JS, Xu H. Mechanistic Investigations on Microbial Type I Terpene Synthases through Site-Directed Mutagenesis. SYNTHESIS-STUTTGART 2021. [DOI: 10.1055/a-1675-8208] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
AbstractDuring the past three decades many terpene synthases have been characterised from all kingdoms of life. Enzymes of type I, from bacteria, fungi and protists, commonly exhibit several highly conserved motifs and single residues, and the available crystal structures show a shared α-helical fold, while the overall sequence identity is generally low. Several enzymes have been studied by site-directed mutagenesis, giving valuable insights into terpene synthase catalysis and the intriguing mechanisms of terpene synthases. Some mutants are also preparatively useful and give higher yields than the wild type or a different product that is otherwise difficult to access. The accumulated knowledge obtained from these studies is presented and discussed in this review.1 Introduction2 Residues for Substrate Binding and Catalysis3 Residues with Structural Function4 Residues Contouring the Active Site Cavity5 Other Residues6 Conclusions
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Lauterbach L, Dickschat JS. Sesquiterpene synthases for bungoene, pentalenene and epi-isozizaene from Streptomyces bungoensis. Org Biomol Chem 2020; 18:4547-4550. [PMID: 32253407 DOI: 10.1039/d0ob00606h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A sesquiterpene synthase from Streptomyces bungoensis was characterised and produces the new compound bungoene. The enzyme mechanism was deeply investigated using isotopically labelled substrates. Two other enzymes from S. bungoensis made epi-isozizaene and pentalenene. Synthetic oxidative chemistry towards structurally related fusagramineol and pentalenal was explored.
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Affiliation(s)
- 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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Villafana RT, Rampersad SN. Signatures of TRI5, TRI8 and TRI11 Protein Sequences of Fusarium incarnatum-equiseti Species Complex (FIESC) Indicate Differential Trichothecene Analogue Production. Toxins (Basel) 2020; 12:E386. [PMID: 32545314 PMCID: PMC7354511 DOI: 10.3390/toxins12060386] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 06/03/2020] [Accepted: 06/07/2020] [Indexed: 11/24/2022] Open
Abstract
The variability and phylogeny among TRI5, TRI8 and TRI11 nucleotide and translated protein sequences of isolates from Trinidad belonging to Fusarium incarnatum-equiseti species complex (FIESC) were compared with FIESC reference sequences. Taxa appeared to be more divergent when DNA sequences were analyzed compared to protein sequences. Neutral and non-neutral mutations in TRI protein sequences that may correspond to variability in the function and structure of the selected TRI proteins were identified. TRI5p had the lowest amino acid diversity with zero predicted non-neutral mutations. TRI5p had potentially three protein disorder regions compared to TRI8p with five protein disorder regions. The deduced TRI11p was more conserved than TRI8p of the same strains. Amino acid substitutions that may be non-neutral to protein function were only detected in diacetoxyscirpenol (DAS) and fusarenon-X (FUS-X) producers of the reference sequence subset for TRI8p and TRI11p. The deduced TRI5 and TRI8 amino acid sequences were mapped to known 3D-structure models and indicated that variations in specific protein order/disorder regions exist in these sequences which affect the overall structural conservation of TRI proteins. Assigning single or combination non-neutral mutations to a particular toxicogenic phenotype may be more representative of potential compared to using genotypic data alone, especially in the absence of wet-lab, experimental validation.
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Affiliation(s)
| | - Sephra N. Rampersad
- Department of Life Sciences, Faculty of Science and Technology, The University of the West Indies, St. Augustine, Trinidad and Tobago, West Indies;
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10
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Affiliation(s)
- Jeroen S. Dickschat
- Kekulé-Institut für Organische Chemie und BiochemieRheinische Friedrich-Wilhelms-Universität Bonn Gerhard-Domagk-Straße 1 53121 Bonn Deutschland
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11
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Abstract
This Minireview summarises recent developments in the biosynthesis of diterpenes by diterpene synthases in bacteria. It is structured by the class of enzyme involved in the first committed step towards diterpenes, starting with type I diterpene synthases, followed by type II enzymes and the more recently discovered UbiA-related diterpene synthases. A special emphasis lies on the reaction mechanisms of diterpene synthases that convert simple linear precursors through cationic cascades into structurally complex, usually polycyclic carbon skeletons with multiple stereogenic centres. A further main focus of this Minireview is a discussion of how these mechanisms can be unravelled. Downstream modifications to bioactive molecules are also covered.
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Affiliation(s)
- Jeroen S Dickschat
- Kekulé-Institute for Organic Chemistry and Biochemistry, Rheinische Friedrich-Wilhelms University of Bonn, Gerhard-Domagk-Strasse 1, 53121, Bonn, Germany
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12
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Vattekkatte A, Garms S, Brandt W, Boland W. Enhanced structural diversity in terpenoid biosynthesis: enzymes, substrates and cofactors. Org Biomol Chem 2019; 16:348-362. [PMID: 29296983 DOI: 10.1039/c7ob02040f] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The enormous diversity of terpenes found in nature is generated by enzymes known as terpene synthases, or cyclases. Some are also known for their ability to convert a single substrate into multiple products. This review comprises monoterpene and sesquiterpene synthases that are multiproduct in nature along with the regulation factors that can alter the product specificity of multiproduct terpene synthases without genetic mutations. Variations in specific assay conditions with focus on shifts in product specificity based on change in metal cofactors, assay pH and substrate geometry are described. Alterations in these simple cellular conditions provide the organism with enhanced chemodiversity without investing into new enzymatic architecture. This versatility to modulate product diversity grants organisms, especially immobile ones like plants with access to an enhanced defensive repertoire by simply altering cofactors, pH level and substrate geometry.
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Affiliation(s)
- Abith Vattekkatte
- Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Hans-Knöll-Strasse 8, D-07745 Jena, Germany.
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13
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Rinkel J, Köllner TG, Chen F, Dickschat JS. Characterisation of three terpene synthases for β-barbatene, β-araneosene and nephthenol from social amoebae. Chem Commun (Camb) 2019; 55:13255-13258. [DOI: 10.1039/c9cc07681f] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Three terpene synthases from social amoebae with new functions were discovered and their mechanisms were explored.
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Affiliation(s)
- Jan Rinkel
- Kekulé-Institut für Organische Chemie und Biochemie
- Rheinische Friedrich-Wilhelms-Universität Bonn
- Gerhard-Domagk-Straße 1
- 53121 Bonn
- Germany
| | - Tobias G. Köllner
- Max Planck Institute for Chemical Ecology
- Hans-Knöll-Straße 8
- 07745 Jena
- Germany
| | - Feng Chen
- Department of Plant Sciences
- University of Tennessee
- 2431 Joe Johnson Drive
- Knoxville
- USA
| | - Jeroen S. Dickschat
- Kekulé-Institut für Organische Chemie und Biochemie
- Rheinische Friedrich-Wilhelms-Universität Bonn
- Gerhard-Domagk-Straße 1
- 53121 Bonn
- Germany
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Rinkel J, Lauterbach L, Dickschat JS. Spata-13,17-diene Synthase-An Enzyme with Sesqui-, Di-, and Sesterterpene Synthase Activity from Streptomyces xinghaiensis. Angew Chem Int Ed Engl 2017; 56:16385-16389. [DOI: 10.1002/anie.201711142] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Jan Rinkel
- 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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15
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Spata-13,17-dien-Synthase - ein Enzym mit Sesqui-, Di- und Sesterterpen-Synthase-Aktivität aus Streptomyces xinghaiensis. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201711142] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Kumari I, Ahmed M, Akhter Y. Evolution of catalytic microenvironment governs substrate and product diversity in trichodiene synthase and other terpene fold enzymes. Biochimie 2017; 144:9-20. [PMID: 29017925 DOI: 10.1016/j.biochi.2017.10.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 10/05/2017] [Indexed: 12/19/2022]
Abstract
Trichodiene synthase, a terpene fold enzyme catalyzes the first reaction of trichodermin biosynthesis that is an economically important secondary metabolite. Sequence search analysis revealed that the proteins containing terpene fold are present in bacteria, fungi and plants. Terpene fold protein from Selaginella moellendorffii, a lycophyte, appeared at the interface of the microbes and plants in the evolutionary scale. Amino acid residues present around the catalytic pocket determines the size of the substrate as well as product molecules. It has been observed that the overall molecular evolution of the catalytic pockets dictates the choice of substrates/products of the proteins. It was further observed that N-terminus of multi-domain terpene fold proteins may assist in the interactions with the pyrophosphate part of the substrates. The phylogenetic analysis of these proteins further revealed that the enzymes are clustered into groups based on the domains present additional to the catalytic domains. We have also observed inter-domain 'puckering forceps' type motions in the multi-domains using normal mode analysis which were further correlated with their functions. The evolutionary clustering of these proteins was also influenced by the presence/absence of cofactor interacting motifs. These results may be used to modify/enhance the functions of these enzymes using protein engineering methods.
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Affiliation(s)
- Indu Kumari
- School of Earth and Environmental Sciences, Central University of Himachal Pradesh, Kangra, Himachal Pradesh, 176206, India
| | - Mushtaq Ahmed
- School of Earth and Environmental Sciences, Central University of Himachal Pradesh, Kangra, Himachal Pradesh, 176206, India
| | - Yusuf Akhter
- School of Life Sciences, Central University of Himachal Pradesh, Kangra, Himachal Pradesh, 176206, India.
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Abstract
![]()
The
year 2017 marks the twentieth anniversary of terpenoid cyclase
structural biology: a trio of terpenoid cyclase structures reported
together in 1997 were the first to set the foundation for understanding
the enzymes largely responsible for the exquisite chemodiversity of
more than 80000 terpenoid natural products. Terpenoid cyclases catalyze
the most complex chemical reactions in biology, in that more than
half of the substrate carbon atoms undergo changes in bonding and
hybridization during a single enzyme-catalyzed cyclization reaction.
The past two decades have witnessed structural, functional, and computational
studies illuminating the modes of substrate activation that initiate
the cyclization cascade, the management and manipulation of high-energy
carbocation intermediates that propagate the cyclization cascade,
and the chemical strategies that terminate the cyclization cascade.
The role of the terpenoid cyclase as a template for catalysis is paramount
to its function, and protein engineering can be used to reprogram
the cyclization cascade to generate alternative and commercially important
products. Here, I review key advances in terpenoid cyclase structural
and chemical biology, focusing mainly on terpenoid cyclases and related
prenyltransferases for which X-ray crystal structures have informed
and advanced our understanding of enzyme structure and function.
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Affiliation(s)
- David W Christianson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania , 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, United States
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Maeda K, Nakajima Y, Motoyama T, Kondoh Y, Kawamura T, Kanamaru K, Ohsato S, Nishiuchi T, Yoshida M, Osada H, Kobayashi T, Kimura M. Identification of a trichothecene production inhibitor by chemical array and library screening using trichodiene synthase as a target protein. PESTICIDE BIOCHEMISTRY AND PHYSIOLOGY 2017; 138:1-7. [PMID: 28456298 DOI: 10.1016/j.pestbp.2017.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 02/20/2017] [Accepted: 03/21/2017] [Indexed: 06/07/2023]
Abstract
Trichothecene mycotoxins often accumulate in apparently normal grains of cereal crops. In an effort to develop an agricultural chemical to reduce trichothecene contamination, we screened trichothecene production inhibitors from the compounds on the chemical arrays. By using the trichodiene (TDN) synthase tagged with hexahistidine (rTRI5) as a target protein, 32 hit compounds were obtained from chemical library of the RIKEN Natural Product Depository (NPDepo) by chemical array screening. At 10μgmL-1, none of the 32 chemicals inhibited trichothecene production by Fusarium graminearum in liquid culture. Against the purified rTRI5 enzyme, however, NPD10133 [progesterone 3-(O-carboxymethyl)oxime amide-bonded to phenylalanine] showed weak inhibitory activity at 10μgmL-1 (18.7μM). For the screening of chemicals inhibiting trichothecene accumulation in liquid culture, 20 analogs of NPD10133 selected from the NPDepo chemical library were assayed. At 10μM, only NPD352 [testosterone 3-(O-carboxymethyl)oxime amide-bonded to phenylalanine methyl ester] inhibited rTRI5 activity and trichothecene production. Kinetic analysis suggested that the enzyme inhibition was of a mixed-type. The identification of NPD352 as a TDN synthase inhibitor lays the foundation for the development of a more potent inhibitor via systematic introduction of wide structural diversity on the gonane skeleton and amino acid residues.
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Affiliation(s)
- Kazuyuki Maeda
- Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan; Graduate School of Agriculture, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Yuichi Nakajima
- Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan; Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Takayuki Motoyama
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yasumitsu Kondoh
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tatsuro Kawamura
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Kyoko Kanamaru
- Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Shuichi Ohsato
- Graduate School of Agriculture, Meiji University, 1-1-1 Higashi-Mita, Tama-ku, Kawasaki, Kanagawa 214-8571, Japan
| | - Takumi Nishiuchi
- Division of Functional Genomics, Advanced Science Research Centre, Kanazawa University, 13-1 Takaramachi, Kanazawa, Ishikawa 920-0934, Japan
| | - Minoru Yoshida
- Chemical Genetics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Hiroyuki Osada
- Chemical Genomics Research Group, RIKEN Center for Sustainable Resource Science, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Tetsuo Kobayashi
- Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan
| | - Makoto Kimura
- Department of Biological Mechanisms and Functions, Graduate School of Bioagricultural Sciences, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8601, Japan.
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19
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Shaw JJ, Berbasova T, Sasaki T, Jefferson-George K, Spakowicz DJ, Dunican BF, Portero CE, Narváez-Trujillo A, Strobel SA. Identification of a fungal 1,8-cineole synthase from Hypoxylon sp. with specificity determinants in common with the plant synthases. J Biol Chem 2015; 290:8511-26. [PMID: 25648891 DOI: 10.1074/jbc.m114.636159] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Terpenes are an important and diverse class of secondary metabolites widely produced by fungi. Volatile compound screening of a fungal endophyte collection revealed a number of isolates in the family Xylariaceae, producing a series of terpene molecules, including 1,8-cineole. This compound is a commercially important component of eucalyptus oil used in pharmaceutical applications and has been explored as a potential biofuel additive. The genes that produce terpene molecules, such as 1,8-cineole, have been little explored in fungi, providing an opportunity to explore the biosynthetic origin of these compounds. Through genome sequencing of cineole-producing isolate E7406B, we were able to identify 11 new terpene synthase genes. Expressing a subset of these genes in Escherichia coli allowed identification of the hyp3 gene, responsible for 1,8-cineole biosynthesis, the first monoterpene synthase discovered in fungi. In a striking example of convergent evolution, mutational analysis of this terpene synthase revealed an active site asparagine critical for water capture and specificity during cineole synthesis, the same mechanism used in an unrelated plant homologue. These studies have provided insight into the evolutionary relationship of fungal terpene synthases to those in plants and bacteria and further established fungi as a relatively untapped source of this important and diverse class of compounds.
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Affiliation(s)
- Jeffrey J Shaw
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Tetyana Berbasova
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Tomoaki Sasaki
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Kyra Jefferson-George
- the Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, and
| | - Daniel J Spakowicz
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Brian F Dunican
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520
| | - Carolina E Portero
- the Laboratorio de Biotecnología Vegetal, Pontificia Universidad Católica del Ecuador, Quito 17 01 21 84, Ecuador
| | - Alexandra Narváez-Trujillo
- the Laboratorio de Biotecnología Vegetal, Pontificia Universidad Católica del Ecuador, Quito 17 01 21 84, Ecuador
| | - Scott A Strobel
- From the Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520,
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20
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Li R, Chou WKW, Himmelberger JA, Litwin KM, Harris GG, Cane DE, Christianson DW. Reprogramming the chemodiversity of terpenoid cyclization by remolding the active site contour of epi-isozizaene synthase. Biochemistry 2014; 53:1155-68. [PMID: 24517311 PMCID: PMC3985761 DOI: 10.1021/bi401643u] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The class I terpenoid cyclase epi-isozizaene synthase (EIZS) utilizes the universal achiral isoprenoid substrate, farnesyl diphosphate, to generate epi-isozizaene as the predominant sesquiterpene cyclization product and at least five minor sesquiterpene products, making EIZS an ideal platform for the exploration of fidelity and promiscuity in a terpenoid cyclization reaction. The hydrophobic active site contour of EIZS serves as a template that enforces a single substrate conformation, and chaperones subsequently formed carbocation intermediates through a well-defined mechanistic sequence. Here, we have used the crystal structure of EIZS as a guide to systematically remold the hydrophobic active site contour in a library of 26 site-specific mutants. Remolded cyclization templates reprogram the reaction cascade not only by reproportioning products generated by the wild-type enzyme but also by generating completely new products of diverse structure. Specifically, we have tripled the overall number of characterized products generated by EIZS. Moreover, we have converted EIZS into six different sesquiterpene synthases: F96A EIZS is an (E)-β-farnesene synthase, F96W EIZS is a zizaene synthase, F95H EIZS is a β-curcumene synthase, F95M EIZS is a β-acoradiene synthase, F198L EIZS is a β-cedrene synthase, and F96V EIZS and W203F EIZS are (Z)-γ-bisabolene synthases. Active site aromatic residues appear to be hot spots for reprogramming the cyclization cascade by manipulating the stability and conformation of critical carbocation intermediates. A majority of mutant enzymes exhibit only relatively modest 2-100-fold losses of catalytic activity, suggesting that residues responsible for triggering substrate ionization readily tolerate mutations deeper in the active site cavity.
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Affiliation(s)
- Ruiqiong Li
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania , Philadelphia, Pennsylvania 19104-6323, United States
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21
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Chen YL, Chiu HT. Trichodiene Synthase: Synthesis and Inhibition Kinetics of 12-Fluoro-farnesylphosphonophosphate for Sesquiterpene Cyclases. J CHIN CHEM SOC-TAIP 2013. [DOI: 10.1002/jccs.200600154] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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22
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Faraldos JA, Gonzalez V, Allemann RK. The role of aristolochene synthase in diphosphate activation. Chem Commun (Camb) 2012; 48:3230-2. [PMID: 22349314 DOI: 10.1039/c2cc17588f] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Analysis of the role of amino acids involved in diphosphate binding in the Michaelis complex of aristolochene synthase from P. roqueforti (PR-AS) reveals mechanistic details about leaving group (PPi) activation and the nature of the active site acid.
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Affiliation(s)
- Juan A Faraldos
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, UK
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23
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Engels B, Heinig U, Grothe T, Stadler M, Jennewein S. Cloning and characterization of an Armillaria gallica cDNA encoding protoilludene synthase, which catalyzes the first committed step in the synthesis of antimicrobial melleolides. J Biol Chem 2010; 286:6871-8. [PMID: 21148562 PMCID: PMC3044942 DOI: 10.1074/jbc.m110.165845] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Melleolides and related fungal sesquiterpenoid aryl esters are antimicrobial and cytotoxic natural products derived from cultures of the Homobasidiomycetes genus Armillaria. The initial step in the biosynthesis of all melleolides involves cyclization of the universal sesquiterpene precursor farnesyl diphosphate to produce protoilludene, a reaction catalyzed by protoilludene synthase. We achieved the partial purification of protoilludene synthase from a mycelial culture of Armillaria gallica and found that 6-protoilludene was its exclusive reaction product. Therefore, a further isomerization reaction is necessary to convert the 6–7 double bond into the 7–8 double bond found in melleolides. We expressed an A. gallica protoilludene synthase cDNA in Escherichia coli, and this also led to the exclusive production of 6-protoilludene. Sequence comparison of the isolated sesquiterpene synthase revealed a distant relationship to other fungal terpene synthases. The isolation of the genomic sequence identified the 6-protoilludene synthase to be present as a single copy gene in the genome of A. gallica, possessing an open reading frame interrupted with eight introns.
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Affiliation(s)
- Benedikt Engels
- Fraunhofer Institut für Molekularbiologie und Angewandte Ökologie, Forckenbeckstrasse 6, 52074 Aachen, Germany
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24
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Aaron JA, Christianson DW. Trinuclear Metal Clusters in Catalysis by Terpenoid Synthases. ACTA ACUST UNITED AC 2010; 82:1585-1597. [PMID: 21562622 DOI: 10.1351/pac-con-09-09-37] [Citation(s) in RCA: 101] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Terpenoid synthases are ubiquitous enzymes that catalyze the formation of structurally and stereochemically diverse isoprenoid natural products. Many isoprenoid coupling enzymes and terpenoid cyclases from bacteria, fungi, protists, plants, and animals share the class I terpenoid synthase fold. Despite generally low amino acid sequence identity among these examples, class I terpenoid synthases contain conserved metal binding motifs that coordinate to a trinuclear metal cluster. This cluster not only serves to bind and orient the flexible isoprenoid substrate in the precatalytic Michaelis complex, but it also triggers the departure of the diphosphate leaving group to generate a carbocation that initiates catalysis. Additional conserved hydrogen bond donors assist the metal cluster in this function. Crystal structure analysis reveals that the constellation of three metal ions required for terpenoid synthase catalysis is generally identical among all class I terpenoid synthases of known structure.
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Affiliation(s)
- Julie A Aaron
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA, 19104-6323, USA
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25
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Agger S, Lopez-Gallego F, Schmidt-Dannert C. Diversity of sesquiterpene synthases in the basidiomycete Coprinus cinereus. Mol Microbiol 2009; 72:1181-95. [PMID: 19400802 DOI: 10.1111/j.1365-2958.2009.06717.x] [Citation(s) in RCA: 128] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Fungi are a rich source of bioactive secondary metabolites, and mushroom-forming fungi (Agaricomycetes) are especially known for the synthesis of numerous bioactive and often cytotoxic sesquiterpenoid secondary metabolites. Compared with the large number of sesquiterpene synthases identified in plants, less than a handful of unique sesquiterpene synthases have been described from fungi. Here we describe the functional characterization of six sesquiterpene synthases (Cop1 to Cop6) and two terpene-oxidizing cytochrome P450 monooxygenases (Cox1 and Cox2) from Coprinus cinereus. The genes were cloned and, except for cop5, functionally expressed in Escherichia coli and/or Saccharomyces cerevisiae. Cop1 and Cop2 each synthesize germacrene A as the major product. Cop3 was identified as an alpha-muurolene synthase, an enzyme that has not been described previously, while Cop4 synthesizes delta-cadinene as its major product. Cop6 was originally annotated as a trichodiene synthase homologue but instead was found to catalyse the highly specific synthesis of alpha-cuprenene. Coexpression of cop6 and the two monooxygenase genes next to it yields oxygenated alpha-cuprenene derivatives, including cuparophenol, suggesting that these genes encode the enzymes for the biosynthesis of antimicrobial quinone sesquiterpenoids (known as lagopodins) that were previously isolated from C. cinereus and other Coprinus species.
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Affiliation(s)
- Sean Agger
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, 1479 Gortner Avenue, St Paul, MN 55108, USA
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26
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Huang Z, Jiang K, Pi Y, Hou R, Liao Z, Cao Y, Han X, Wang Q, Sun X, Tang K. Molecular cloning and characterization of the yew gene encoding squalene synthase from Taxus cuspidata. BMB Rep 2008; 40:625-35. [PMID: 17927893 DOI: 10.5483/bmbrep.2007.40.5.625] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The enzyme squalene synthase (EC 2.5.1.21) catalyzes a reductive dimerization of two farnesyl diphosphate (FPP) molecules into squalene, a key precursor for the sterol and triterpene biosynthesis. A full-length cDNA encoding squalene synthase (designated as TcSqS) was isolated from Taxus cuspidata, a kind of important medicinal plants producing potent anti-cancer drug, taxol. The full-length cDNA of TcSqS was 1765 bp and contained a 1230 bp open reading frame (ORF) encoding a polypeptide of 409 amino acids. Bioinformatic analysis revealed that the deduced TcSqS protein had high similarity with other plant squalene synthases and a predicted crystal structure similar to other class I isoprenoid biosynthetic enzymes. Southern blot analysis revealed that there was one copy of TcSqS gene in the genome of T. cuspidata. Semiquantitative RT-PCR analysis and northern blotting analysis showed that TcSqS expressed constitutively in all tested tissues, with the highest expression in roots. The promoter region of TcSqS was also isolated by genomic walking and analysis showed that several cis-acting elements were present in the promoter region. The results of treatment experiments by different signaling components including methyl-jasmonate, salicylic acid and gibberellin revealed that the TcSqS expression level of treated cells had a prominent diversity to that of control, which was consistent with the prediction results of TcSqS promoter region in the PlantCARE database.
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Affiliation(s)
- Zhuosh Huang
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Fudan-SJTU-Nottingham Plant Biotechnology R&D Center, Morgan-Tan International Center for Life Sciences, Fudan University, Shanghai 200433, People's Republic of China
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27
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Vedula LS, Zhao Y, Coates RM, Koyama T, Cane DE, Christianson DW. Exploring biosynthetic diversity with trichodiene synthase. Arch Biochem Biophys 2007; 466:260-6. [PMID: 17678871 PMCID: PMC2036078 DOI: 10.1016/j.abb.2007.06.016] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2007] [Revised: 06/14/2007] [Accepted: 06/15/2007] [Indexed: 11/30/2022]
Abstract
Trichodiene synthase is a terpenoid cyclase that catalyzes the cyclization of farnesyl diphosphate (FPP) to form the bicyclic sesquiterpene hydrocarbon trichodiene (89%), at least five sesquiterpene side products (11%), and inorganic pyrophosphate (PP(i)). Incubation of trichodiene synthase with 2-fluorofarnesyl diphosphate or 4-methylfarnesyl diphosphate similarly yields sesquiterpene mixtures despite the electronic effects or steric bulk introduced by substrate derivatization. The versatility of the enzyme is also demonstrated in the 2.85A resolution X-ray crystal structure of the complex with Mg(2+) (3)-PP(i) and the benzyl triethylammonium cation, which is a bulkier mimic of the bisabolyl carbocation intermediate in catalysis. Taken together, these findings show that the active site of trichodiene synthase is sufficiently flexible to accommodate bulkier and electronically-diverse substrates and intermediates, which could indicate additional potential for the biosynthetic utility of this terpenoid cyclase.
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Affiliation(s)
- L Sangeetha Vedula
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
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28
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Affiliation(s)
- David W Christianson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA.
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29
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The Trichothecenes and Their Biosynthesis. PROGRESS IN THE CHEMISTRY OF ORGANIC NATURAL PRODUCTS 2007. [DOI: 10.1007/978-3-211-49389-2_2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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30
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Shishova EY, Di Costanzo L, Cane DE, Christianson DW. X-ray crystal structure of aristolochene synthase from Aspergillus terreus and evolution of templates for the cyclization of farnesyl diphosphate. Biochemistry 2007; 46:1941-51. [PMID: 17261032 PMCID: PMC2518937 DOI: 10.1021/bi0622524] [Citation(s) in RCA: 133] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Aristolochene synthase from Aspergillus terreus catalyzes the cyclization of the universal sesquiterpene precursor, farnesyl diphosphate, to form the bicyclic hydrocarbon aristolochene. The 2.2 A resolution X-ray crystal structure of aristolochene synthase reveals a tetrameric quaternary structure in which each subunit adopts the alpha-helical class I terpene synthase fold with the active site in the "open", solvent-exposed conformation. Intriguingly, the 2.15 A resolution crystal structure of the complex with Mg2+3-pyrophosphate reveals ligand binding only to tetramer subunit D, which is stabilized in the "closed" conformation required for catalysis. Tetramer assembly may hinder conformational changes required for the transition from the inactive open conformation to the active closed conformation, thereby accounting for the attenuation of catalytic activity with an increase in enzyme concentration. In both conformations, but especially in the closed conformation, the active site contour is highly complementary in shape to that of aristolochene, and a catalytic function is proposed for the pyrophosphate anion based on its orientation with regard to the presumed binding mode of aristolochene. A similar active site contour is conserved in aristolochene synthase from Penicillium roqueforti despite the substantial divergent evolution of these two enzymes, while strikingly different active site contours are found in the sesquiterpene cyclases 5-epi-aristolochene synthase and trichodiene synthase. Thus, the terpenoid cyclase active site plays a critical role as a template in binding the flexible polyisoprenoid substrate in the proper conformation for catalysis. Across the greater family of terpenoid cyclases, this template is highly evolvable within a conserved alpha-helical fold for the synthesis of terpene natural products of diverse structure and stereochemistry.
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Affiliation(s)
| | | | | | - David W. Christianson
- *To whom correspondence should be addressed at the Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 St., Philadelphia, Pennsylvania 19104-6323. Phone: 215-898-5714. Fax: 215-573-2201. E-mail:
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31
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Brück TB, Kerr RG. Purification and kinetic properties of elisabethatriene synthase from the coral Pseudopterogorgia elisabethae. Comp Biochem Physiol B Biochem Mol Biol 2006; 143:269-78. [PMID: 16423548 DOI: 10.1016/j.cbpb.2005.11.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2005] [Revised: 11/07/2005] [Accepted: 11/14/2005] [Indexed: 11/15/2022]
Abstract
The Bahamian octocoral Pseudopterogorgia elisabethae is the source of pseudopterosins, diterpene glycosides with potent anti-inflammatory activity. The first committed step in pseudopterosin biosynthesis comprises the cyclisation of the universal diterpene precursor geranylgeranyl diphosphate to elisabethatriene. This reaction is catalysed by elisabethatriene synthase, which was purified to homogeneity from a crude coral extract. This represents the first purification to apparent homogeneity of a terpene cyclase from any marine source. The reaction kinetics of elisabethatriene synthase was examined using a steady state approach with (3)H-labelled isoprenyldiphosphates varying in carbon chain length (C(10), C(15), C(20)). For the reaction of elisabethatriene synthase with its natural substrate geranylgeranyl diphosphate, values of K(m) (2.3 x 10(-6) M), V(max) (3.4 x 10(4) nM elisabethatriene x s(-1)) and the specificity constant (k(cat)/K(m)= 1.8 x 10(-10) M(-1) x s(-1)) were comparable with diterpene cyclases from terrestrial plants. Elisabethatriene synthase also catalysed the conversion of C(15) and C(10) isoprenyldiphosphate analogues to monoterpene and sesquiterpene olefins, respectively. Kinetic parameters indicated that substrate specificity and K(m) of elisabethatriene synthase decreased with decreasing isoprenoid carbon chain length. Furthermore, GC-MS analysis showed increased product diversity with decreasing isoprenoid carbon chain length.
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Affiliation(s)
- Thomas B Brück
- Department of Chemistry and Biochemistry, Center of Excellence in Biomedical and Marine Biotechnology, Florida Atlantic University, 777 Glades Rd., Boca Raton, 33431, USA
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32
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Vedula LS, Cane DE, Christianson DW. Role of arginine-304 in the diphosphate-triggered active site closure mechanism of trichodiene synthase. Biochemistry 2005; 44:12719-27. [PMID: 16171386 PMCID: PMC1386727 DOI: 10.1021/bi0510476] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
The X-ray crystal structures of R304K trichodiene synthase and its complexes with inorganic pyrophosphate (PP(i)) and aza analogues of the bisabolyl carbocation intermediate are reported. The R304K substitution does not cause large changes in the overall structure in comparison with the wild-type enzyme. The complexes with (R)- and (S)-azabisabolenes and PP(i) bind three Mg2+ ions, and each undergoes a diphosphate-triggered conformational change that caps the active site cavity. This conformational change is only slightly attenuated compared to that of the wild-type enzyme complexed with Mg2+(3)-PP(i), in which R304 donates hydrogen bonds to PP(i) and D101. In R304K trichodiene synthase, K304 does not engage in any hydrogen bond interactions in the unliganded state and it donates a hydrogen bond to only PP(i) in the complex with (R)-azabisabolene; K304 makes no hydrogen bond contacts in its complex with PP(i) and (S)-azabisabolene. Thus, although the R304-D101 hydrogen bond interaction stabilizes diphosphate-triggered active site closure, it is not required for Mg2+(3)-PP(i) binding. Nevertheless, since R304K trichodiene synthase generates aberrant cyclic terpenoids with a 5000-fold reduction in kcat/KM, it is clear that a properly formed R304-D101 hydrogen bond is required in the enzyme-substrate complex to stabilize the proper active site contour, which in turn facilitates cyclization of farnesyl diphosphate for the exclusive formation of trichodiene. Structural analysis of the R304K mutant and comparison with the monoterpene cyclase (+)-bornyl diphosphate synthase suggest that the significant loss in activity results from compromised activation of the PP(i) leaving group.
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Affiliation(s)
| | | | - David W. Christianson
- To whom correspondence should be addressed at the Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34 St., Philadelphia, PA 19104-6323 [215-898-5714 (phone); 215-573-2201 (fax); (e-mail)]
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33
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Hyatt DC, Croteau R. Mutational analysis of a monoterpene synthase reaction: altered catalysis through directed mutagenesis of (-)-pinene synthase from Abies grandis. Arch Biochem Biophys 2005; 439:222-33. [PMID: 15978541 DOI: 10.1016/j.abb.2005.05.017] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2005] [Revised: 05/13/2005] [Accepted: 05/13/2005] [Indexed: 11/16/2022]
Abstract
Two monoterpene synthases, (-)-pinene synthase and (-)-camphene synthase, from grand fir (Abies grandis) produce different product mixtures despite having highly homologous amino acid sequences and, presumably, very similar three-dimensional structures. The major product of (-)-camphene synthase, (-)-camphene, and the major products of (-)-pinene synthase, (-)-alpha-pinene, and (-)-beta-pinene, arise through distinct mechanistic variations of the electrophilic reaction cascade that is common to terpenoid synthases. Structural modeling followed by directed mutagenesis in (-)-pinene synthase was used to replace selected amino acid residues with the corresponding residues from (-)-camphene synthase in an effort to identify the amino acids responsible for the catalytic differences. This approach produced an enzyme in which more than half of the product was channeled through an alternative pathway. It was also shown that several (-)-pinene synthase to (-)-camphene synthase amino acid substitutions were necessary before catalysis was significantly altered. The data support a model in which the collective action of many key amino acids, located both in and distant from the active site pocket, regulate the course of the electrophilic reaction cascade.
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Affiliation(s)
- David C Hyatt
- Institute of Biological Chemistry, Washington State University, Pullman, 99163-6340, USA
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Wu S, Schoenbeck MA, Greenhagen BT, Takahashi S, Lee S, Coates RM, Chappell J. Surrogate splicing for functional analysis of sesquiterpene synthase genes. PLANT PHYSIOLOGY 2005; 138:1322-33. [PMID: 15965019 PMCID: PMC1176406 DOI: 10.1104/pp.105.059386] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
A method for the recovery of full-length cDNAs from predicted terpene synthase genes containing introns is described. The approach utilizes Agrobacterium-mediated transient expression coupled with a reverse transcription-polydeoxyribonucleotide chain reaction assay to facilitate expression cloning of processed transcripts. Subsequent expression of intronless cDNAs in a suitable prokaryotic host provides for direct functional testing of the encoded gene product. The method was optimized by examining the expression of an intron-containing beta-glucuronidase gene agroinfiltrated into petunia (Petunia hybrida) leaves, and its utility was demonstrated by defining the function of two previously uncharacterized terpene synthases. A tobacco (Nicotiana tabacum) terpene synthase-like gene containing six predicted introns was characterized as having 5-epi-aristolochene synthase activity, while an Arabidopsis (Arabidopsis thaliana) gene previously annotated as a terpene synthase was shown to possess a novel sesquiterpene synthase activity for alpha-barbatene, thujopsene, and beta-chamigrene biosynthesis.
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Affiliation(s)
- Shuiqin Wu
- Plant Physiology, Biochemistry and Molecular Biology Program, Department of Plant and Soil Sciences, University of Kentucky, Lexington, Kentucky 40546-0312
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35
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Katoh S, Hyatt D, Croteau R. Altering product outcome in Abies grandis (−)-limonene synthase and (−)-limonene/(−)-α-pinene synthase by domain swapping and directed mutagenesis. Arch Biochem Biophys 2004; 425:65-76. [PMID: 15081895 DOI: 10.1016/j.abb.2004.02.015] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2004] [Revised: 02/12/2004] [Indexed: 10/26/2022]
Abstract
(-)-(4S)-limonene synthase (LS) and (-)-(4S)-limonene/(-)-(1S, 5S)-alpha-pinene synthase (LPS) from grand fir (Abies grandis) exhibit nearly 91% sequence identity (93% similarity) at the amino acid level, yet produce very different mixtures of monoterpene olefins. To elucidate critical amino acids involved in determining monoterpene product distribution, a combination of domain swapping and reciprocal site-directed mutagenesis was carried out between these two enzymes. Exchange of the predicted helix D through F region in LS gave rise to an LPS-like product outcome, whereas reciprocal substitutions of four amino acids in LPS (two in the predicted helix D and two in the predicted helix F) altered the product distribution to that intermediate between LS and LPS, and resulted in a 5-fold increase in relative velocity. These results, in conjunction with modeling of the two enzymes, suggest that amino acids in the predicted D through F helix regions are critical for product determination.
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Affiliation(s)
- Sadanobu Katoh
- Institute of Biological Chemistry, Washington State University, Pullman, Washington 99164-6340, USA
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Hicks LM, O'Connor SE, Mazur MT, Walsh CT, Kelleher NL. Mass Spectrometric Interrogation of Thioester-Bound Intermediates in the Initial Stages of Epothilone Biosynthesis. ACTA ACUST UNITED AC 2004; 11:327-35. [PMID: 15123262 DOI: 10.1016/j.chembiol.2004.02.021] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2003] [Revised: 12/09/2003] [Accepted: 12/11/2003] [Indexed: 10/26/2022]
Abstract
Direct detection of thioester intermediate mixtures bound to EpoC, a 195 kDa polyketide synthase, has been achieved using limited proteolysis and Fourier-transform mass spectrometry (FTMS). Incubation with various N-acetylcysteamine thioester (S-NAC) substrate mimics produced mass shifts on the EpoC ACP domain consistent with their condensation with an enzyme-bound carbanion produced by the decarboxylation of methylmalonyl-S-EpoC. Reconstitution of EpoA-ACP, EpoB, and EpoC gave a +165.0 Da mass shift consistent with the formation of the methylthiazolyl-methacrylyl product by incorporation of acetyl-CoA, cysteine, and methylmalonyl-CoA. Thioester-templated reaction intermediates and products are typically characterized by quantifying radioactive substrates, either enzyme bound or chemically hydrolyzed. In contrast, the MS-based methodology described here provides semiquantifiable ratios of free enzyme, intermediate, and product occupancy and reveals that certain substrates result in a >50% formation of nonproductive intermediates.
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Affiliation(s)
- Leslie M Hicks
- Department of Chemistry, 600 South Mathews Avenue, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Segura MJR, Jackson BE, Matsuda SPT. Mutagenesis approaches to deduce structure-function relationships in terpene synthases. Nat Prod Rep 2003; 20:304-17. [PMID: 12828369 DOI: 10.1039/b008338k] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This review highlights mutagenesis studies of terpene synthases, specifically sesquiterpene synthases and oxidosqualene cyclases. Mutagenesis studies of these enzymes have provided mechanistic insights, structure-function relationships for specific enzymatic residues, novel terpene structures and enzymes with novel activities. The literature through 2002 is reviewed and 113 references cited.
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Umeno D, Tobias AV, Arnold FH. Evolution of the C30 carotenoid synthase CrtM for function in a C40 pathway. J Bacteriol 2002; 184:6690-9. [PMID: 12426357 PMCID: PMC135437 DOI: 10.1128/jb.184.23.6690-6699.2002] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The C30 carotene synthase CrtM from Staphylococcus aureus and the C40 carotene synthase CrtB from Erwinia uredovora were swapped into their respective foreign C40 and C30 biosynthetic pathways (heterologously expressed in Escherichia coli) and evaluated for function. Each displayed negligible ability to synthesize the natural carotenoid product of the other. After one round of mutagenesis and screening, we isolated 116 variants of CrtM able to synthesize C40 carotenoids. In contrast, we failed to find a single variant of CrtB with detectable C30 activity. Subsequent analysis revealed that the best CrtM mutants performed comparably to CrtB in an in vivo C40 pathway. These mutants showed significant variation in performance in their original C30 pathway, indicating the emergence of enzymes with broadened substrate specificity as well as those with shifted specificity. We discovered that Phe 26 alone determines the specificity of CrtM. The plasticity of CrtM with respect to its substrate and product range highlights the potential for creating further new carotenoid backbone structures.
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Affiliation(s)
- Daisuke Umeno
- Department of Chemical Engineering, California Institute of Technology 210-41, Pasadena, California 91125, USA.
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Rynkiewicz MJ, Cane DE, Christianson DW. Structure of trichodiene synthase from Fusarium sporotrichioides provides mechanistic inferences on the terpene cyclization cascade. Proc Natl Acad Sci U S A 2001; 98:13543-8. [PMID: 11698643 PMCID: PMC61077 DOI: 10.1073/pnas.231313098] [Citation(s) in RCA: 210] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2001] [Indexed: 11/18/2022] Open
Abstract
The x-ray crystal structure of recombinant trichodiene synthase from Fusarium sporotrichioides has been determined to 2.5-A resolution, both unliganded and complexed with inorganic pyrophosphate. This reaction product coordinates to three Mg(2+) ions near the mouth of the active site cleft. A comparison of the liganded and unliganded structures reveals a ligand-induced conformational change that closes the mouth of the active site cleft. Binding of the substrate farnesyl diphosphate similarly may trigger this conformational change, which would facilitate catalysis by protecting reactive carbocationic intermediates in the cyclization cascade. Trichodiene synthase also shares significant structural similarity with other sesquiterpene synthases despite a lack of significant sequence identity. This similarity indicates divergence from a common ancestor early in the evolution of terpene biosynthesis.
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Affiliation(s)
- M J Rynkiewicz
- Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104-6323, USA
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40
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Cyclization Enzymes in the Biosynthesis of Monoterpenes, Sesquiterpenes, and Diterpenes. BIOSYNTHESIS 2000. [DOI: 10.1007/3-540-48146-x_2] [Citation(s) in RCA: 284] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
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Abstract
The 10-cyclopropylidene analog of farnesyl diphosphate was shown to be a mechanism-based inhibitor of trichodiene synthase with an inactivation rate (k(inact)) of 0.010 +/- 0.0003 min(-1) and an apparent Ki of 663 +/- 75 nM. The presence of three anomalous sesquiterpene products detected in incubation mixtures indicate that the compound also serves as a substrate of the enzyme.
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Affiliation(s)
- D E Cane
- Department of Chemistry, Brown University, Providence, RI 02912, USA
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Lesburg CA, Caruthers JM, Paschall CM, Christianson DW. Managing and manipulating carbocations in biology: terpenoid cyclase structure and mechanism. Curr Opin Struct Biol 1998; 8:695-703. [PMID: 9914250 DOI: 10.1016/s0959-440x(98)80088-2] [Citation(s) in RCA: 99] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Terpenoid cyclases catalyze remarkably complex cyclization cascades that are initiated by the formation of a highly reactive carbocation in a polyisoprene substrate. Recent crystal structures of terpenoid cyclases show how these enzymes provide a template for binding and stabilizing the flexible substrate in the precise orientation required for catalysis, trigger carbocation formation, chaperone the conformations of the reactive carbocation intermediates through a unique cyclization sequence, and sequester and stabilize carbocations from premature quenching. Notably, terpenoid cyclases and catalytic antibodies have converged to similar chemical and structural strategies for managing highly reactive carbocations in polyisoprene cyclization cascades.
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Affiliation(s)
- C A Lesburg
- Department of Structural Chemistry Schering-Plough Research Institute 2015 Galloping Hill Road Kenilworth NJ 07033-0539 USA
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Bohlmann J, Meyer-Gauen G, Croteau R. Plant terpenoid synthases: molecular biology and phylogenetic analysis. Proc Natl Acad Sci U S A 1998; 95:4126-33. [PMID: 9539701 PMCID: PMC22453 DOI: 10.1073/pnas.95.8.4126] [Citation(s) in RCA: 645] [Impact Index Per Article: 24.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
This review focuses on the monoterpene, sesquiterpene, and diterpene synthases of plant origin that use the corresponding C10, C15, and C20 prenyl diphosphates as substrates to generate the enormous diversity of carbon skeletons characteristic of the terpenoid family of natural products. A description of the enzymology and mechanism of terpenoid cyclization is followed by a discussion of molecular cloning and heterologous expression of terpenoid synthases. Sequence relatedness and phylogenetic reconstruction, based on 33 members of the Tps gene family, are delineated, and comparison of important structural features of these enzymes is provided. The review concludes with an overview of the organization and regulation of terpenoid metabolism, and of the biotechnological applications of terpenoid synthase genes.
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Affiliation(s)
- J Bohlmann
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA.
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Huang K, Huang QL, Scott AI. Overexpression, single-step purification, and site-directed mutagenetic analysis of casbene synthase. Arch Biochem Biophys 1998; 352:144-52. [PMID: 9521827 DOI: 10.1006/abbi.1998.0578] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Casbene synthase is a diterpene cyclase isolated from castor bean (Ricinus communis L), which catalyzes the cyclization of geranylgeranyl diphosphate to form the phytoalexin casbene. We here report the overexpression of casbene synthase in Escherichia coli in soluble form using a thioredoxin fusion system. The amplified DNA by PCR carried on pCS7 was inserted into the expression vector pET32b(+) to form pCAS.2. The resulting transformants of pCAS. 2/BL21(DE3) produced a thioredoxin casbene synthase fusion protein (20-30% of total soluble protein) when induced with isopropyl beta-d-thiogalactopyranoside at 20 degrees C. Recombinant casbene synthase was purified to homogeneity in a single step with a His-binding metal-affinity column. Casbene synthase has a conserved aspartate-rich region [amino acids 355-359 (DDTID)], one cysteine, and three histidines with several prenyl transferases and terpene cyclases. Seven mutants were constructed by site-directed mutagenesis. The importance of Asp 355 and Asp 356 for catalysis was established by an increase in Km as well as a reduction in kcat in the corresponding glutamate mutants. These results indicate that the first and the second aspartate are involved in catalysis, while the third aspartate and the conserved cysteine and histidine residues selected for mutagenesis appear not to be involved in catalysis.
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Affiliation(s)
- K Huang
- Chemistry Department, Texas A&M University, College Station, Texas 77843-3255, USA
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Fekete C, Logrieco A, Giczey G, Hornok L. Screening of fungi for the presence of the trichodiene synthase encoding sequence by hybridization to the Tri5 gene cloned from Fusarium poae. Mycopathologia 1998; 138:91-7. [PMID: 9433809 DOI: 10.1023/a:1006882704594] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
A trichodiene synthase gene (Tri5) was amplified from F. poae by polymerase chain reaction using synthetic primers constructed on the basis of the coding portion of the same gene from F. sporotrichioides. Sequence analysis showed a high degree of similarity with other trichodiene synthase genes. A 378 bp HindIII fragment of the gene that contains the genetic information for the putative active site of the trichodiene synthase enzyme was radiolabelled and used for dot blot analysis. This probe could detect Tri5 hybridization in 1-10 ng DNA of fusaria that have the genetic potentiality to synthesize toxic trichothecene compounds, but gave no reaction with trichothecene nonproducing members of the genus. When other fungi reported to produce trichothecenes (Myrothecium, Stachybotrys, Trichoderma, Trichothecium spp.) were tested, only strains of Myrothecium and Stachybotrys gave strong positive reaction. Faint but consistent hybridization signals were obtained in four species (F. semitectum, F. tricinctum, Trichoderma viride and Trichothecium roseum) indicating the presence of nonhomologous evolutionary variants or inactive remnants of the Tri5 gene in these fungi.
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Affiliation(s)
- C Fekete
- Agricultural Biotechnology Center, Gödöllö, Hungary
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47
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Devarenne TP, Shin DH, Back K, Yin S, Chappell J. Molecular characterization of tobacco squalene synthase and regulation in response to fungal elicitor. Arch Biochem Biophys 1998; 349:205-15. [PMID: 9448707 DOI: 10.1006/abbi.1997.0463] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The enzyme squalene synthase (SS) represents the first commitment of carbon from the general isoprenoid pathway toward sterol biosynthesis and is a potential point for regulation of sterol biosynthesis. The isolation and characterization of tobacco (Nicotiana tabacum) squalene synthase (TSS) cDNA and genomic DNA clones, as well as determination of the steady state level of TSS mRNA in response to elicitor treatment, were investigated. cDNA clones for TSS were isolated from poly (A)+ RNA using a reverse transcription/polymerase chain reaction (RT/PCR) method. A 1233-bp cDNA clone was generated that contained an open reading frame of 411 amino acids giving a predicted molecular mass of 46.9 kDa. Comparison of the TSS deduced amino acid sequence with currently described SS from different species showed the highest identify with Nicotiana benthamiana (97%), followed by Glycyrrhiza glabra (81%), Arabidopsis thaliana (74%), rat (40%), and yeast (37%). Expression of a soluble form of the TSS enzyme with enzymatic activity in Escherichia coli was achieved by truncating 24 hydrophobic amino acids at the carboxy terminus. Characterization of genomic TSS (gTSS) revealed a gene of 7.086 kb with a complex organization of small exons and large introns not typical of plant genes. Southern blot hybridization indicated only two copies of the SS gene in the tobacco genome. Treatment of tobacco cell suspension cultures with a fungal elicitor dramatically reduced TSS enzymatic activity, lowering it to zero within 24 h. Analysis of TSS mRNA levels, by RNA blot hybridization and primer extension assays, in elicitor-treated cells indicated that the transcript level remained largely unchanged over this 24-h period. These results suggest that the suppression of TSS enzyme activity in elicitor-treated cells may result from a posttranscriptional modification of TSS.
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Affiliation(s)
- T P Devarenne
- Agronomy Department, University of Kentucky, Lexington 40546-0091, USA
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48
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Bouvier F, d'Harlingue A, Camara B. Molecular analysis of carotenoid cyclase inhibition. Arch Biochem Biophys 1997; 346:53-64. [PMID: 9328284 DOI: 10.1006/abbi.1997.0278] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Later steps of carotenoid biosynthesis catalyzed by cyclase enzymes involve the formation of alpha, beta, and kappa-rings. Examination of the primary structure of lycopene beta-cyclase revealed 55% identity with that of antheraxanthin kappa-cyclase. Recombinant lycopene beta-cyclase afforded only beta-carotene, while recombinant antheraxanthin kappa-cyclase catalyzed the formation of beta-carotene from lycopene as well as the conversion of antheraxanthin into the kappa-carotenoid capsanthin. Since the formation of beta- and kappa-rings involves a transient carotenoid carbocation, this suggests that both cyclases initiate and/or neutralize the incipient carbocation by similar mechanisms. Several amine derivatives protonated at physiological pH were used to examine the molecular basis of this phenomenon. The beta-and kappa-cyclases displayed similar inhibition patterns. Affinity or photoaffinity labeling using p-dimethylamino-benzenediazonium fluoroborate, N,N-dimethyl-2-phenylaziridinium, and nicotine irreversibly inactivated both cyclase enzymes. Photoaffinity labeling using [3H]nicotine followed by radiosequence analysis and site-directed mutagenesis revealed the existence of two cyclase domains characterized by the presence of reactive aromatic and carboxylic amino acid residues. We propose that these residues represent the "negative point charges" involved in the coordination of the incipient carotenoid carbocations.
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Affiliation(s)
- F Bouvier
- Institut de Biologie Moléculaire des Plantes du Centre National de la Recherche Scientifique, Université Louis Pasteur, Strasbourg, France
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Mathis JR, Back K, Starks C, Noel J, Poulter CD, Chappell J. Pre-steady-state study of recombinant sesquiterpene cyclases. Biochemistry 1997; 36:8340-8. [PMID: 9204881 DOI: 10.1021/bi963019g] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
An Escherichia coli expression system was used to generate hexahistidyl-tagged plant sesquiterpene cyclases, which were readily purified by a single affinity chromatographic step. Genes for Hyoscyamus muticus vetispiradiene synthase (HVS), a chimeric 5-epi-aristolochene synthase (CH3), and a chimeric sesquiterpene cyclase possessing multifunctional epi-aristolochene and vetispiradiene activity (CH4) were expressed in bacterial cells, which resulted in the sesquiterpene cyclases accumulating to 50% of the total protein and 35% of the soluble protein. From initial velocity experiments, the Michaelis constant for HVS was 3.5 microM, while CH3 and CH4 exhibited smaller values of 0.7 and 0.4 microM, respectively. Steady-state catalytic constants were from 0.02 to 0.04 s-1. A combination of pre-steady-state rapid quench experiments, isotope trapping experiments, and experiments to measure the burst rate constant as a function of substrate concentration revealed that turnover in all three cyclases is limited by a step after the initial chemical step involving rupture of the carbon-oxygen bond in farnesyl diphosphate (FPP). Rate constants for the limiting step were 10-70-fold smaller than for the initial chemical step. Dissociation constants for the enzyme-substrate complex (20-70 microM) were determined from the pre-steady-state experiments and were significantly larger than the observed Michaelis constants. A mechanism that involves an initial, rapid equilibration of enzyme with substrate to form an enzyme-substrate complex, followed by a slower conversion of FPP to an enzyme-bound hydrocarbon and a subsequent rate-limiting step, is proposed for the three enzymes. Interestingly, the multifunctional chimeric enzyme CH4 exhibited both a tighter binding of FPP and a faster conversion of FPP to products than either of its wild-type parents.
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Affiliation(s)
- J R Mathis
- Department of Chemistry, University of Utah, Salt Lake City, Utah 84112, USA
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50
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Affiliation(s)
- P M Dewick
- Department of Pharmaceutical Sciences, University of Nottingham, UK
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