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Singh VK, Nallasivam JL, Chakraborty TK. One-Pot Tandem Aldol-Cycloetherification Protocol in the Enantioselective Synthesis of Davanoids. J Org Chem 2023. [PMID: 36811497 DOI: 10.1021/acs.joc.2c02865] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
Total synthesis of cis and trans diastereomers of prenylated davanoids like davanone, nordavanone, and davana acid ethyl ester was achieved in an enantioselective strategy. Various other davanoids could also be synthesized using standard procedures from the Weinreb amides derived from davana acids. Enantioselectivity in our synthesis was achieved employing a Crimmins' non-Evans syn aldol reaction that fixed the stereochemistry of the C3-hydroxyl group, while the C2-methyl group was epimerized in a late stage of the synthesis. A Lewis acid-mediated cycloetherification reaction was used to establish the tetrahydrofuran core of these molecules. Interestingly, a slight alteration of the Crimmins' non-Evans syn aldol protocol led to the complete conversion of the aldol adduct to the core tetrahydrofuran ring of davanoids, thus essentially dovetailing two important steps in the synthesis. The resulting one-pot tandem aldol-cycloetherification strategy enabled the enantioselective synthesis of trans davana acid ethyl esters and 2-epi-davanone/nordavanone in just three steps in excellent overall yields. The modularity of the approach will enable the synthesis of various other isomers in stereochemically pure forms for further biological profiling of this important class of molecules.
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Affiliation(s)
- Vipin Kumar Singh
- Department of Organic Chemistry, Indian Institute of Science, Bengaluru 560012, India
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2
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Leferink NGH, Ranaghan KE, Karuppiah V, Currin A, van der Kamp MW, Mulholland AJ, Scrutton NS. Experiment and Simulation Reveal How Mutations in Functional Plasticity Regions Guide Plant Monoterpene Synthase Product Outcome. ACS Catal 2019; 8:3780-3791. [PMID: 31157124 PMCID: PMC6542672 DOI: 10.1021/acscatal.8b00692] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Monoterpenes (C10 isoprenoids) are a structurally diverse group of natural compounds that are attractive to industry as flavours and fragrances. Monoterpenes are produced from a single linear substrate, geranyl diphosphate, by a group of enzymes called the monoterpene cyclases/synthases (mTC/Ss) that catalyse high-energy cyclisation reactions involving unstable carbocation intermediates. Efforts towards producing monoterpenes via biocatalysis or metabolic engineering often result in the formation of multiple products due to the nature of the highly branched reaction mechanism of mTC/Ss. Rational engineering of mTC/Ss is hampered by the lack of correlation between the active site sequence and cyclisation type. We used available mutagenesis data to show that amino acids involved in product outcome are clustered and spatially conserved within the mTC/S family. Consensus sequences for three such plasticity regions were introduced in different mTC/S with increasingly complex cyclisation cascades, including the model enzyme limonene synthase (LimS). In all three mTC/S studied, mutations in the first two regions mostly give rise to products that result from premature quenching of the linalyl or α-terpinyl cations, suggesting that both plasticity regions are involved in the formation and stabilisation of cations early in the reaction cascade. A LimS variant with mutations in the second region (S454G, C457V, M458I), produced mainly more complex bicyclic products. QM/MM MD simulations reveal that the second cyclisation is not due to compression of the C2-C7 distance in the α-terpinyl cation, but is the result of an increased distance between C8 of the α-terpinyl cation and two putative bases (W324, H579) located on the other side of the active site, preventing early termination by deprotonation. Such insights into the impact of mutations can only be obtained using integrated experimental and computational approaches, and will aid the design of altered mTC/S activities towards clean monoterpenoid products.
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Affiliation(s)
- Nicole G. H. Leferink
- Manchester Synthetic Biology Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, Faculty of Science and Engineering, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Kara E. Ranaghan
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Vijaykumar Karuppiah
- Manchester Synthetic Biology Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, Faculty of Science and Engineering, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Andrew Currin
- Manchester Synthetic Biology Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, Faculty of Science and Engineering, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
| | - Marc W. van der Kamp
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
- School of Biochemistry, University of Bristol, Biomedical Sciences Building, University Walk, Bristol BS8 1TD, U.K
| | - Adrian J. Mulholland
- Centre for Computational Chemistry, School of Chemistry, University of Bristol, Cantock’s Close, Bristol BS8 1TS, U.K
| | - Nigel S. Scrutton
- Manchester Synthetic Biology Research Centre for Fine and Speciality Chemicals (SYNBIOCHEM), Manchester Institute of Biotechnology, School of Chemistry, Faculty of Science and Engineering, University of Manchester, 131 Princess Street, Manchester M1 7DN, U.K
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3
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Lange BM, Srividya N. Enzymology of monoterpene functionalization in glandular trichomes. JOURNAL OF EXPERIMENTAL BOTANY 2019; 70:1095-1108. [PMID: 30624688 DOI: 10.1093/jxb/ery436] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Accepted: 11/18/2018] [Indexed: 05/08/2023]
Abstract
The plant kingdom supports an extraordinary chemical diversity, with terpenoids representing a particularly diversified class of secondary (or specialized) metabolites. Volatile and semi-volatile terpenoids in the C10-C20 range are often formed in specialized cell types and secretory structures. In the angiosperm lineage, glandular trichomes play an important role in enabling the biosynthesis and storage (or in some cases secretion) of functionalized terpenoids. The 'decoration' of a terpenoid scaffold with functional groups changes its physical and chemical properties, and can therefore affect the perception of a specific metabolite by other organisms. Because of the ecological implications (e.g. plant-herbivore interactions) and commercial relevance (e.g. volatiles used in the flavor and fragrance industries), terpenoid functionalization has been researched extensively. Recent successes in the cloning and functional evaluation of genes as well as the structural and biochemical characterization of enzyme catalysts have laid the foundation for an improved understanding of how pathways toward functionalized monoterpenes may have evolved. In this review, we will focus on an up-to-date account of functionalization reactions present in glandular trichomes.
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Affiliation(s)
- Bernd Markus Lange
- Institute of Biological Chemistry and M.J. Murdock Metabolomics Laboratory, Washington State University, Pullman, USA
| | - Narayanan Srividya
- Institute of Biological Chemistry and M.J. Murdock Metabolomics Laboratory, Washington State University, Pullman, USA
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4
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Yao J, Chen F, Guo H. QM/MM free energy simulations of the reaction catalysed by (4S)-limonene synthase involving linalyl diphosphate (LPP) substrate. MOLECULAR SIMULATION 2018. [DOI: 10.1080/08927022.2018.1447106] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- Jianzhuang Yao
- School of Biological Science and Technology, University of Jinan , Jinan, P.R. China
| | - Feng Chen
- Department of Plant Sciences, University of Tennessee , Knoxville, TN, USA
| | - Hong Guo
- Department of Biochemistry and Cellular and Molecular Biology, University of Tennessee, Knoxville, TN, USA
- UT/ORNL Center for Molecular Biophysics, Oak Ridge National Laboratory, Oak Ridge, TN, USA
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Abstract
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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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6
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Zhang F, Chen N, Zhou J, Wu R. Protonation-Dependent Diphosphate Cleavage in FPP Cyclases and Synthases. ACS Catal 2016. [DOI: 10.1021/acscatal.6b02096] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Fan Zhang
- School
of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People’s Republic of China
| | - Nanhao Chen
- School
of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People’s Republic of China
- Department
of Chemistry, University of California, Davis, California 95616, United States
| | - Jingwei Zhou
- School
of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People’s Republic of China
| | - Ruibo Wu
- School
of Pharmaceutical Sciences, Sun Yat-sen University, Guangzhou 510006, People’s Republic of China
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Shinde SS, Navale GR, Said MS, Thulasiram HV. Stereoselective quenching of cedryl carbocation in epicedrol biosynthesis. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.01.109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Citron CA, Rabe P, Barra L, Nakano C, Hoshino T, Dickschat JS. Synthesis of Isotopically Labelled Oligoprenyl Diphosphates and Their Application in Mechanistic Investigations of Terpene Cyclases. European J Org Chem 2014. [DOI: 10.1002/ejoc.201403002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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9
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Catalytic control in terpenoid cyclases: multiscale modeling of thermodynamic, kinetic, and dynamic effects. Curr Opin Chem Biol 2014; 21:25-33. [DOI: 10.1016/j.cbpa.2014.03.010] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Accepted: 03/09/2014] [Indexed: 02/08/2023]
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Doron D, Weitman M, Vardi-Kilshtain A, Azuri A, Engel H, Major DT. Multiscale Quantum-Classical Simulations of Enzymes. Isr J Chem 2014. [DOI: 10.1002/ijch.201400026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Major DT, Weitman M. Electrostatically guided dynamics--the root of fidelity in a promiscuous terpene synthase? J Am Chem Soc 2012; 134:19454-62. [PMID: 23101787 DOI: 10.1021/ja308295p] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Terpene cyclases are responsible for the initial cyclization cascade in the multistep synthesis of more than 60,000 known natural products. This abundance of compounds is generated using a very limited pool of substrates based on linear isoprenoids. The astounding chemodiversity obtained by terpene cyclases suggests a tremendous catalytic challenge to these often promiscuous enzymes. In the current study we present a detailed mechanistic view of the biosynthesis of the monoterpene bornyl diphosphate (BPP) from geranyl diphosphate by BPP synthase using state of the art simulation methods. We identify the bornyl cation as an enzyme-induced bifurcation point on the multidimensional free energy surface, connecting between the product BPP and the side product camphene. Chemical dynamics simulations suggest that the active site diphosphate moiety steers reaction trajectories toward product formation. Nonetheless, chemical dynamics is not precise enough for exclusive product formation, providing a rationale for the lack of fidelity in this promiscuous terpene cyclase.
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Affiliation(s)
- Dan Thomas Major
- Department of Chemistry and the Lise Meitner-Minerva Center of Computational Quantum Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel.
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12
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Köksal M, Chou WKW, Cane DE, Christianson DW. Structure of 2-methylisoborneol synthase from Streptomyces coelicolor and implications for the cyclization of a noncanonical C-methylated monoterpenoid substrate. Biochemistry 2012; 51:3011-20. [PMID: 22455514 DOI: 10.1021/bi201827a] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
The crystal structure of 2-methylisoborneol synthase (MIBS) from Streptomyces coelicolor A3(2) has been determined in complex with substrate analogues geranyl-S-thiolodiphosphate and 2-fluorogeranyl diphosphate at 1.80 and 1.95 Å resolution, respectively. This terpenoid cyclase catalyzes the cyclization of the naturally occurring, noncanonical C-methylated isoprenoid substrate, 2-methylgeranyl diphosphate, to form the bicyclic product 2-methylisoborneol, a volatile C(11) homoterpene alcohol with an earthy, musty odor. While MIBS adopts the tertiary structure of a class I terpenoid cyclase, its dimeric quaternary structure differs from that previously observed in dimeric terpenoid cyclases from plants and fungi. The quaternary structure of MIBS is nonetheless similar in some respects to that of dimeric farnesyl diphosphate synthase, which is not a cyclase. The structures of MIBS complexed with substrate analogues provide insights regarding differences in the catalytic mechanism of MIBS and the mechanisms of (+)-bornyl diphosphate synthase and endo-fenchol synthase, plant cyclases that convert geranyl diphosphate into products with closely related bicyclic bornyl skeletons, but distinct structures and stereochemistries.
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Affiliation(s)
- Mustafa Köksal
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, 231 South 34th Street, Philadelphia, Pennsylvania 19104-6323, USA
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13
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Weitman M, Major DT. Challenges posed to bornyl diphosphate synthase: diverging reaction mechanisms in monoterpenes. J Am Chem Soc 2010; 132:6349-60. [PMID: 20394387 DOI: 10.1021/ja910134x] [Citation(s) in RCA: 83] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The simplest form of terpenoid chemistry is found for the monoterpenes, which give plants fragrance, flavor, and medicinal properties. Monoterpene synthases employ geranyl diphosphate as a substrate to generate an assortment of cyclic products. In the current study we present a detailed analysis of the multiple gas-phase reaction pathways in the synthesis of bornyl cation from geranyl diphosphate. Additionally, the fate of the proposed bornyl cation intermediate in the bornyl diphosphate synthase reaction is investigated by molecular dynamics simulations. We employ accurate density functional theory (DFT) methods after careful validation against high-level ab initio data for a set of model carbocations. The gas-phase results for the monoterpene reactions indicate a diverging reaction mechanism with multiple products in the absence of enzymatic control. This complex potential energy surface includes several possible bifurcation points due to the presence of secondary cations. Additionally, the suggested bornyl cation intermediate in the bornyl diphosphate synthase reaction is studied by molecular dynamics simulations employing a hybrid quantum mechanics (DFT)-molecular mechanics potential energy function. The simulations suggest that the bornyl cation is a transient species as in the gas phase and that electrostatic steering directs the formation of the final product, bornyl diphosphate.
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Affiliation(s)
- Michal Weitman
- Department of Chemistry and the Lise Meitner-Minerva Center of Computational Quantum Chemistry, Bar-Ilan University, Ramat-Gan 52900, Israel
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14
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Karp F, Zhao Y, Santhamma B, Assink B, Coates RM, Croteau RB. Inhibition of monoterpene cyclases by inert analogues of geranyl diphosphate and linalyl diphosphate. Arch Biochem Biophys 2007; 468:140-6. [PMID: 17949678 DOI: 10.1016/j.abb.2007.09.008] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 09/09/2007] [Accepted: 09/13/2007] [Indexed: 11/17/2022]
Abstract
The tightly coupled nature of the reaction sequence catalyzed by monoterpene synthases has prevented direct observation of the topologically required isomerization step leading from geranyl diphosphate to the enzyme-bound, tertiary allylic intermediate linalyl diphosphate, which then cyclizes to the various monoterpene skeletons. X-ray crystal structures of these enzymes complexed with suitable analogues of the substrate and intermediate could provide a clearer view of this universal, but cryptic, step of monoterpenoid cyclase catalysis. Toward this end, the functionally inert analogues 2-fluorogeranyl diphosphate, (+/-)-2-fluorolinalyl diphosphate, and (3R)- and (3S)-homolinalyl diphosphates (2,6-dimethyl-2-vinyl-5-heptenyl diphosphates) were prepared, and compared to the previously described substrate analogue 3-azageranyl diphosphate (3-aza-2,3-dihydrogeranyl diphosphate) as inhibitors and potential crystallization aids with two representative monoterpenoid cyclases, (-)-limonene synthase and (+)-bornyl diphosphate synthase. Although these enantioselective synthases readily distinguished between (3R)- and (3S)-homolinalyl diphosphates, both of which were more effective inhibitors than was 3-azageranyl diphosphate, the fluorinated analogues proved to be the most potent competitive inhibitors and have recently yielded informative liganded structures with limonene synthase.
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Affiliation(s)
- Frank Karp
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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15
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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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16
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Tsangarakis C, Stratakis M. Stereoselective Disposition of the Geminal Dimethyl Group in the Cyclization of Geranyl Acetate under Zeolite Confinement Conditions. European J Org Chem 2006. [DOI: 10.1002/ejoc.200600367] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Quantitative 2H NMR spectroscopy 2. “H/D-Isotope portraits” of cyclic monoterpenes and discrimination of their biosynthetic pathways. Russ Chem Bull 2005. [DOI: 10.1007/s11172-005-0391-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Xu M, Hillwig ML, Prisic S, Coates RM, Peters RJ. Functional identification of rice syn-copalyl diphosphate synthase and its role in initiating biosynthesis of diterpenoid phytoalexin/allelopathic natural products. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2004; 39:309-18. [PMID: 15255861 DOI: 10.1111/j.1365-313x.2004.02137.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Rice produces a number of phytoalexins, and at least one allelopathic agent, from syn-copalyl diphosphate (CPP), representing the only known metabolic fate for this compound. Thus, the class II terpene synthase that converts the universal diterpenoid precursor geranylgeranyl diphosphate to syn-CPP catalyzes the committed step in biosynthesis of these natural products. Here the extensive sequence information available for rice was coupled to recombinant expression and functional analysis to identify syn-copalyl diphosphate synthase (OsCPSsyn). In addition, OsCPSsyn mRNA was found to be specifically induced in leaves by conditions that stimulate phytoalexin biosynthesis. Therefore, transcription of OsCPSsyn seems to be an important regulatory point for controlling the production of these defensive compounds. Finally, alignments carried out with OsCPSsyn revealed that class II terpene synthases exhibit a sequence conservation pattern substantially different from that of the prototypical class I enzymes. One particularly notable feature is the specific conservation of the functionally cryptic 'insertional' sequence element in class II terpene synthases, indicating that this region is important for the corresponding cyclization reaction.
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Affiliation(s)
- Meimei Xu
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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Peters RJ, Croteau RB. Alternative termination chemistries utilized by monoterpene cyclases: chimeric analysis of bornyl diphosphate, 1,8-cineole, and sabinene synthases. Arch Biochem Biophys 2003; 417:203-11. [PMID: 12941302 DOI: 10.1016/s0003-9861(03)00347-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Monoterpene cyclization reactions are initiated by ionization and isomerization of geranyl diphosphate, and proceed, via cyclization of bound linalyl diphosphate, through a series of carbocation intermediates with ultimate termination of the multistep cascade by deprotonation or nucleophile capture. Three structurally and mechanistically related monoterpene cyclases from Salvia officinalis, (+)-sabinene synthase (deprotonation to olefin), 1,8-cineole synthase (water capture), and (+)-bornyl diphosphate synthase (diphosphate capture), were employed to explore the structural determinants of these alternative termination chemistries. Results with chimeric recombinant enzymes, constructed by reciprocally substituting regions of sabinene synthase with the corresponding sequences from bornyl diphosphate synthase or 1,8-cineole synthase, demonstrated that exchange of the C-terminal catalytic domain is sufficient to completely switch the resulting product profile. Exchange of smaller sequence elements identified a region of roughly 70 residues from 1,8-cineole synthase that, when substituted into sabinene synthase, conferred the ability to produce 1,8-cineole. A similar strategy identified a small region of bornyl diphosphate synthase important in conducting the anti-Markovnikov addition to the bornane skeleton. Observations made with these chimeric monoterpene cyclases are discussed in the context of the recently determined crystal structure for bornyl diphosphate synthase.
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Affiliation(s)
- Reuben J Peters
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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Whittington DA, Wise ML, Urbansky M, Coates RM, Croteau RB, Christianson DW. Bornyl diphosphate synthase: structure and strategy for carbocation manipulation by a terpenoid cyclase. Proc Natl Acad Sci U S A 2002; 99:15375-80. [PMID: 12432096 PMCID: PMC137724 DOI: 10.1073/pnas.232591099] [Citation(s) in RCA: 232] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2002] [Indexed: 11/18/2022] Open
Abstract
The x-ray crystal structure of dimeric (+)-bornyl diphosphate synthase, a metal-requiring monoterpene cyclase from Salvia officinalis, is reported at 2.0-A resolution. Each monomer contains two alpha-helical domains: the C-terminal domain catalyzes the cyclization of geranyl diphosphate, orienting and stabilizing multiple reactive carbocation intermediates; the N-terminal domain has no clearly defined function, although its N terminus caps the active site in the C-terminal domain during catalysis. Structures of complexes with aza analogues of substrate and carbocation intermediates, as well as complexes with pyrophosphate and bornyl diphosphate, provide "snapshots" of the terpene cyclization cascade.
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Affiliation(s)
- Douglas A Whittington
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia 19104-6323, USA
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