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Liu H, Fang S, Zhao L, Men X, Zhang H. A Single Active-Site Mutagenesis Confers Enhanced Activity and/or Changed Product Distribution to a Pentalenene Synthase from Streptomyces sp. PSKA01. Bioengineering (Basel) 2023; 10:bioengineering10030392. [PMID: 36978783 PMCID: PMC10045451 DOI: 10.3390/bioengineering10030392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 03/16/2023] [Accepted: 03/20/2023] [Indexed: 03/30/2023] Open
Abstract
Pentalenene is a ternary cyclic sesquiterpene formed via the ionization and cyclization of farnesyl pyrophosphate (FPP), which is catalyzed by pentalenene synthase (PentS). To better understand the cyclization reactions, it is necessary to identify more key sites and elucidate their roles in terms of catalytic activity and product specificity control. Previous studies primarily relied on the crystal structure of PentS to analyze and verify critical active sites in the active cavity, while this study started with the function of PentS and screened a novel key site through random mutagenesis. In this study, we constructed a pentalenene synthetic pathway in E. coli BL21(DE3) and generated PentS variants with random mutations to construct a mutant library. A mutant, PentS-13, with a varied product diversity, was obtained through shake-flask fermentation and product identification. After sequencing and the functional verification of the mutation sites, it was found that T182A, located in the G2 helix, was responsible for the phenotype of PentS-13. The site-saturation mutagenesis of T182 demonstrated that mutations at this site not only affected the solubility and activity of the enzyme but also affected the specificity of the product. The other products were generated through different routes and via different carbocation intermediates, indicating that the 182 active site is crucial for PentS to stabilize and guide the regioselectivity of carbocations. Molecular docking and molecular dynamics simulations suggested that these mutations may induce changes in the shape and volume of the active cavity and disturb hydrophobic/polar interactions that were sufficient to reposition reactive intermediates for alternative reaction pathways. This article provides rational explanations for these findings, which may generally allow for the protein engineering of other terpene synthases to improve their catalytic efficiency or modify their specificities.
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Affiliation(s)
- Hongshuang Liu
- State Key Laboratory of Bio-Based Material and Green Papermaking, School of Bioengineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250316, China
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
| | - Senbiao Fang
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
| | - Lin Zhao
- State Key Laboratory of Bio-Based Material and Green Papermaking, School of Bioengineering, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250316, China
| | - Xiao Men
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
| | - Haibo Zhang
- CAS Key Laboratory of Biobased Materials, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
- Shandong Energy Institute, Qingdao 266101, China
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2
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Xu H, Dickschat JS. Germacrene A-A Central Intermediate in Sesquiterpene Biosynthesis. Chemistry 2020; 26:17318-17341. [PMID: 32442350 PMCID: PMC7821278 DOI: 10.1002/chem.202002163] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 05/20/2020] [Indexed: 01/17/2023]
Abstract
This review summarises known sesquiterpenes whose biosyntheses proceed through the intermediate germacrene A. First, the occurrence and biosynthesis of germacrene A in Nature and its peculiar chemistry will be highlighted, followed by a discussion of 6-6 and 5-7 bicyclic compounds and their more complex derivatives. For each compound the absolute configuration, if it is known, and the reasoning for its assignment is presented.
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Affiliation(s)
- Houchao Xu
- 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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3
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Loizzi M, Miller DJ, Allemann RK. Silent catalytic promiscuity in the high-fidelity terpene cyclase δ-cadinene synthase. Org Biomol Chem 2019; 17:1206-1214. [PMID: 30652178 PMCID: PMC6369673 DOI: 10.1039/c8ob02821d] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aza-analogues of carbocations inhibit δ-cadinene synthase: 1,6-cyclisation.
δ-Cadinene synthase (DCS) is a high-fidelity sesquiterpene synthase that generates δ-cadinene as the sole detectable organic product from its natural substrate (E,E)-FDP. Previous work with this enzyme using substrate analogues revealed the ability of DCS to catalyse both 1,10- and 1,6-cyclisations of substrate analogues. To test whether this apparent promiscuity was an artefact of alternate substrate use or an inherent property of the enzyme, aza analogues of the proposed α-bisabolyl cation intermediate were prepared since this cation would be formed after an initial 1,6-cyclisation of FDP. In the presence of 250 μM inorganic disphosphate both (R)- and (S)-aza-bisaboyl cations were potent competitive inhibitors of DCS (Ki = 2.5 ± 0.5 mM and 3.44 ± 1.43 μM, respectively). These compounds were also shown to be potent inhibitors of the 1,6-cyclase amorpha-4,11-diene synthase but not of the 1,10-cyclase aristolochene synthase from Penicillium roquefortii, demonstrating that the 1,6-cyclase activity of DCS is most likely an inherent property of the enzyme even when the natural substrate is used and not an artefact of the use of substrate analogues.
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Affiliation(s)
- Marianna Loizzi
- School of Chemistry, Cardiff University Main Building, Park Place, Cardiff, CF10 3AT, UK.
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4
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Affiliation(s)
- Shinji Yamada
- Department of Chemistry, Faculty of Science, Ochanomizu University, 2-1-1 Otsuka, Bunkyo-ku, Tokyo 112-8610, Japan
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5
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Abdelmagid WM, Adak T, Freeman JO, Tanner ME. Studies with Guanidinium- and Amidinium-Based Inhibitors Suggest Minimal Stabilization of Allylic Carbocation Intermediates by Dehydrosqualene and Squalene Synthases. Biochemistry 2018; 57:5591-5601. [PMID: 30179505 DOI: 10.1021/acs.biochem.8b00731] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Dehydrosqualene and squalene synthases catalyze the redox neutral and the reductive, head-to-head dimerization of farnesyl diphosphate, respectively. In each case, the reaction is thought to proceed via an initial dissociation of farnesyl diphosphate to form an allylic carbocation-pyrophosphate ion pair. This work describes the synthesis and testing of inhibitors in which a guanidinium or amidinium moiety is flanked by a phosphonylphosphinate group and a hydrocarbon tail. These functional groups bear a planar, delocalized, positive charge and therefore should act as excellent mimics of an allylic carbocation. An inhibitor bearing a neutral urea moiety was also prepared as a control. The positively charged inhibitors acted as competitive inhibitors against Staphylococcus aureus dehydrosqualene synthase with Ki values in the low micromolar range. Surprisingly, the neutral urea inhibitor was the most potent of the three. Similar trends were seen with the first half reaction of human squalene synthase. One interpretation of these results is that the active sites of these enzymes do not directly stabilize the allylic carbocation via electrostatic or π-cation interactions. Instead, it is likely that the enzymes use tight binding to the pyrophosphate and lipid moieties to promote catalysis and that electrostatic stabilization of the carbocation is provided by the bound pyrophosphate product. An alternate possibility is that these inhibitors cannot bind to the "ionization FPP-binding site" of the enzyme and only bind to the "nonionizing FPP-binding site". In either case, all reported attempts to generate potent inhibitors with cationic FPP analogues have been unsuccessful to date.
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Affiliation(s)
- Walid M Abdelmagid
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Taniya Adak
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
| | - Jon O Freeman
- Department of Chemistry , Pacific Lutheran University , Tacoma , Washington 98447 , United States
| | - Martin E Tanner
- Department of Chemistry , University of British Columbia , Vancouver , British Columbia V6T 1Z1 , Canada
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6
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Huynh F, Grundy DJ, Jenkins RL, Miller DJ, Allemann RK. Sesquiterpene Synthase-Catalysed Formation of a New Medium-Sized Cyclic Terpenoid Ether from Farnesyl Diphosphate Analogues. Chembiochem 2018; 19:1834-1838. [PMID: 29802753 PMCID: PMC6334173 DOI: 10.1002/cbic.201800218] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2018] [Indexed: 11/08/2022]
Abstract
Terpene synthases catalyse the first step in the conversion of prenyl diphosphates to terpenoids. They act as templates for their substrates to generate a reactive conformation, from which a Mg2+ -dependent reaction creates a carbocation-PPi ion pair that undergoes a series of rearrangements and (de)protonations to give the final terpene product. This tight conformational control was exploited for the (R)-germacrene A synthase- and germacradien-4-ol synthase-catalysed formation of a medium-sized cyclic terpenoid ether from substrates containing nucleophilic functional groups. Farnesyl diphosphate analogues with a 10,11-epoxide or an allylic alcohol were efficiently converted to a 11-membered cyclic terpenoid ether that was characterised by HRMS and NMR spectroscopic analyses. Further experiments showed that other sesquiterpene synthases, including aristolochene synthase, δ-cadinene synthase and amorphadiene synthase, yielded this novel terpenoid from the same substrate analogues. This work illustrates the potential of terpene synthases for the efficient generation of structurally and functionally novel medium-sized terpene ethers.
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Affiliation(s)
- Florence Huynh
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
| | - Daniel J. Grundy
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
| | - Robert L. Jenkins
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
| | - David J. Miller
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
| | - Rudolf K. Allemann
- School of ChemistryCardiff UniversityMain BuildingPark PlaceCardiffCF10 3ATUK
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7
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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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8
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Faraldos JA, Grundy DJ, Cascon O, Leoni S, van der Kamp MW, Allemann RK. Enzymatic synthesis of natural (+)-aristolochene from a non-natural substrate. Chem Commun (Camb) 2016; 52:14027-14030. [DOI: 10.1039/c6cc08164a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aristolochene synthase from Penicillium roqueforti converts 7-methylene-FDP, a substrate the enzyme never encounters in nature, to the natural product (+)-aristolochene.
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Affiliation(s)
| | | | - Oscar Cascon
- School of Chemistry
- Cardiff University
- Cardiff CF10 3AT
- UK
| | - Stefano Leoni
- School of Chemistry
- Cardiff University
- Cardiff CF10 3AT
- UK
| | - Marc W. van der Kamp
- School of Biochemistry
- Faculty of Biomedical Sciences & Centre for Computational Chemistry
- School of Chemistry
- University of Bristol
- Biomedical Sciences Building
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9
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Vattekkatte A, Gatto N, Schulze E, Brandt W, Boland W. Inhibition of a multiproduct terpene synthase from Medicago truncatula by 3-bromoprenyl diphosphates. Org Biomol Chem 2015; 13:4776-84. [DOI: 10.1039/c5ob00506j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
3-Bromo prenyl analogues bind to the active site and act as competitive inhibitors for terpene cyclases and -synthases.
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Affiliation(s)
- Abith Vattekkatte
- Department of Bioorganic Chemistry
- Max Planck Institute for Chemical Ecology
- D-07745 Jena
- Germany
| | - Nathalie Gatto
- Department of Bioorganic Chemistry
- Max Planck Institute for Chemical Ecology
- D-07745 Jena
- Germany
| | - Eva Schulze
- Department of Bioorganic Chemistry
- Leibniz Institute of Plant Biochemistry
- 06120 Halle (Saale)
- Germany
| | - Wolfgang Brandt
- Department of Bioorganic Chemistry
- Leibniz Institute of Plant Biochemistry
- 06120 Halle (Saale)
- Germany
| | - Wilhelm Boland
- Department of Bioorganic Chemistry
- Max Planck Institute for Chemical Ecology
- D-07745 Jena
- Germany
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10
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van der Kamp MW, Sirirak J, Żurek J, Allemann RK, Mulholland AJ. Conformational change and ligand binding in the aristolochene synthase catalytic cycle. Biochemistry 2013; 52:8094-105. [PMID: 24106830 DOI: 10.1021/bi400898k] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Terpene synthases are potentially useful biocatalysts for the synthesis of valuable compounds, such as anticancer drugs and antibiotics. The design of altered activities requires better knowledge of their mechanisms, for example, an understanding of the complex conformational changes that are part of their catalytic cycle, how they are coordinated, and what drives them. Crystallographic studies of the sesquiterpene synthase artistolochene synthase have led to a proposed sequence of ligand binding and conformational change but have provided only indirect insight. Here, we have performed extensive molecular dynamics simulations of multiple enzyme-ligand complexes (over 2 μs in total). The simulations provide clear evidence of what drives the conformational changes required for reaction. They support a picture in which the substrate farnesyl diphosphate binds first, followed by three magnesium ions in sequence, and, after reaction, the release of aristolochene and two magnesium ions followed by the final magnesium ion and diphosphate. Binding of farnesyl diphosphate leads to an increased level of sampling of open conformations, allowing the first two magnesium ions to bind. The closed enzyme conformation is maintained with a diphosphate moiety and two magnesium ions bound. The open-to-closed transition reduces flexibility around the active site entrance, partly through a lid closing over it. The simulations with all three magnesium ions and farnesyl diphosphate bound provide, for the first time, a realistic model of the Michaelis complex involved in reaction, which is inaccessible to experimental structural studies. These insights could help with the design of altered activities in a range of terpene synthases.
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Affiliation(s)
- Marc W van der Kamp
- Centre for Computational Chemistry, School of Chemistry, University of Bristol , Bristol BS8 1TS, U.K
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11
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Chen M, Al-lami N, Janvier M, D'Antonio EL, Faraldos JA, Cane DE, Allemann RK, Christianson DW. Mechanistic insights from the binding of substrate and carbocation intermediate analogues to aristolochene synthase. Biochemistry 2013; 52:5441-53. [PMID: 23905850 PMCID: PMC3755762 DOI: 10.1021/bi400691v] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Aristolochene synthase, a metal-dependent sesquiterpene cyclase from Aspergillus terreus, catalyzes the ionization-dependent cyclization of farnesyl diphosphate (FPP) to form the bicyclic eremophilane (+)-aristolochene with perfect structural and stereochemical precision. Here, we report the X-ray crystal structure of aristolochene synthase complexed with three Mg(2+) ions and the unreactive substrate analogue farnesyl-S-thiolodiphosphate (FSPP), showing that the substrate diphosphate group is anchored by metal coordination and hydrogen bond interactions identical to those previously observed in the complex with three Mg(2+) ions and inorganic pyrophosphate (PPi). Moreover, the binding conformation of FSPP directly mimics that expected for productively bound FPP, with the exception of the precise alignment of the C-S bond with regard to the C10-C11 π system that would be required for C1-C10 bond formation in the first step of catalysis. We also report crystal structures of aristolochene synthase complexed with Mg(2+)3-PPi and ammonium or iminium analogues of bicyclic carbocation intermediates proposed for the natural cyclization cascade. Various binding orientations are observed for these bicyclic analogues, and these orientations appear to be driven by favorable electrostatic interactions between the positively charged ammonium group of the analogue and the negatively charged PPi anion. Surprisingly, the active site is sufficiently flexible to accommodate analogues with partially or completely incorrect stereochemistry. Although this permissiveness in binding is unanticipated, based on the stereochemical precision of catalysis that leads exclusively to the (+)-aristolochene stereoisomer, it suggests the ability of the active site to enable controlled reorientation of intermediates during the cyclization cascade. Taken together, these structures illuminate important aspects of the catalytic mechanism.
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Affiliation(s)
- Mengbin Chen
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104-6323 USA
| | - Naeemah Al-lami
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales, United Kingdom
| | - Marine Janvier
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales, United Kingdom
| | - Edward L. D'Antonio
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104-6323 USA
| | - Juan A. Faraldos
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales, United Kingdom
| | - David E. Cane
- Department of Chemistry, Box H, Brown University, Providence, RI 02912-9108 USA
| | - Rudolf K. Allemann
- School of Chemistry, Cardiff University, Park Place, Cardiff CF10 3AT, Wales, United Kingdom
| | - David W. Christianson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania, 19104-6323 USA,To whom correspondence should be addressed: Department of Chemistry, University of Pennsylvania, 2001 Roy and Diana Vagelos Laboratories, 231 South 34th Street, Philadelphia, PA, 19104-6323 USA. Tel: 215-898-5714;
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12
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Faraldos JA, Miller DJ, González V, Yoosuf-Aly Z, Cascón O, Li A, Allemann RK. A 1,6-ring closure mechanism for (+)-δ-cadinene synthase? J Am Chem Soc 2012; 134:5900-8. [PMID: 22397618 DOI: 10.1021/ja211820p] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Recombinant (+)-δ-cadinene synthase (DCS) from Gossypium arboreum catalyzes the metal-dependent cyclization of (E,E)-farnesyl diphosphate (FDP) to the cadinane sesquiterpene δ-cadinene, the parent hydrocarbon of cotton phytoalexins such as gossypol. In contrast to some other sesquiterpene cyclases, DCS carries out this transformation with >98% fidelity but, as a consequence, leaves no mechanistic traces of its mode of action. The formation of (+)-δ-cadinene has been shown to occur via the enzyme-bound intermediate (3R)-nerolidyl diphosphate (NDP), which in turn has been postulated to be converted to cis-germacradienyl cation after a 1,10-cyclization. A subsequent 1,3-hydride shift would then relocate the carbocation within the transient macrocycle to expedite a second cyclization that yields the cadinenyl cation with the correct cis stereochemistry found in (+)-δ-cadinene. An elegant 1,10-mechanistic pathway that avoids the formation of (3R)-NDP has also been suggested. In this alternative scenario, the final cadinenyl cation is proposed to be formed through the intermediacy of trans, trans-germacradienyl cation and germacrene D. In addition, an alternative 1,6-ring closure mechanism via the bisabolyl cation has previously been envisioned. We report here a detailed investigation of the catalytic mechanism of DCS using a variety of mechanistic probes including, among others, deuterated and fluorinated FDPs. Farnesyl diphosphate analogues with fluorine at C2 and C10 acted as inhibitors of DCS, but intriguingly, after prolonged overnight incubations, they yielded 2F-germacrene(s) and a 10F-humulene, respectively. The observed 1,10-, and to a lesser extent, 1,11-cyclization activity of DCS with these fluorinated substrates is consistent with the postulated macrocyclization mechanism(s) en route to (+)-δ-cadinene. On the other hand, mechanistic results from incubations of DCS with 6F-FPP, (2Z,6E)-FDP, neryl diphosphate, 6,7-dihydro-FDP, and NDP seem to be in better agreement with the potential involvement of the alternative biosynthetic 1,6-ring closure pathway. In particular, the strong inhibition of DCS by 6F-FDP, coupled to the exclusive bisabolyl- and terpinyl-derived product profiles observed for the DCS-catalyzed turnover of (2Z,6E)-farnesyl and neryl diphosphates, suggested the intermediacy of α-bisabolyl cation. DCS incubations with enantiomerically pure [1-(2)H(1)](1R)-FDP revealed that the putative bisabolyl-derived 1,6-pathway proceeds through (3R)-nerolidyl diphosphate (NDP), is consistent with previous deuterium-labeling studies, and accounts for the cis stereochemistry characteristic of cadinenyl-derived sesquiterpenes. While the results reported here do not unambiguously rule in favor of 1,6- or 1,10-cyclization, they demonstrate the mechanistic versatility inherent to DCS and highlight the possible existence of multiple mechanistic pathways.
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Affiliation(s)
- Juan A Faraldos
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, United Kingdom
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13
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Miller DJ, Allemann RK. Sesquiterpene synthases: Passive catalysts or active players? Nat Prod Rep 2012; 29:60-71. [DOI: 10.1039/c1np00060h] [Citation(s) in RCA: 109] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Cascón O, Touchet S, Miller DJ, Gonzalez V, Faraldos JA, Allemann RK. Chemoenzymatic preparation of germacrene analogues. Chem Commun (Camb) 2012; 48:9702-4. [DOI: 10.1039/c2cc35542f] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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15
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Affiliation(s)
- Braulio M Fraga
- Instituto de Productos Naturales y Agrobiología, CSIC, 38206-La Laguna, Tenerife, Canary Islands, Spain.
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16
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Faraldos JA, González V, Senske M, Allemann RK. Templating effects in aristolochene synthase catalysis: elimination versus cyclisation. Org Biomol Chem 2011; 9:6920-3. [PMID: 21870004 DOI: 10.1039/c1ob06184d] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Analysis of the products generated by mutants of aristolochene synthase from P. roqueforti (PR-AS) revealed the prominent structural role played by the aliphatic residue Leu 108 in maintaining the productive conformation of farnesyl diphosphate to ensure C1-C10 (σ-bond) ring-closure and hence (+)-aristolochene production.
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Affiliation(s)
- Juan A Faraldos
- School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, United Kingdom
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17
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Faraldos JA, Antonczak AK, González V, Fullerton R, Tippmann EM, Allemann RK. Probing eudesmane cation-π interactions in catalysis by aristolochene synthase with non-canonical amino acids. J Am Chem Soc 2011; 133:13906-9. [PMID: 21815676 DOI: 10.1021/ja205927u] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Stabilization of the reaction intermediate eudesmane cation (3) through interaction with Trp 334 during catalysis by aristolochene synthase from Penicillium roqueforti was investigated by site-directed incorporation of proteinogenic and non-canonical aromatic amino acids. The amount of germacrene A (2) generated by the mutant enzymes served as a measure of the stabilization of 3. 2 is a neutral intermediate, from which 3 is formed during PR-AS catalysis by protonation of the C6,C7 double bond. The replacement of Trp 334 with para-substituted phenylalanines of increasing electron-withdrawing properties led to a progressive accumulation of 2 that showed a good correlation with the interaction energies of simple cations such as Na(+) with substituted benzenes. These results provide compelling evidence for the stabilizing role played by Trp 334 in aristolochene synthase catalysis for the energetically demanding transformation of 2 to 3.
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Affiliation(s)
- Juan A Faraldos
- School of Chemistry, Cardiff University, Park Place, Cardiff, United Kingdom
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