201
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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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202
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Roy A, Roberts FG, Wilderman PR, Zhou K, Peters RJ, Coates RM. 16-Aza-ent-beyerane and 16-Aza-ent-trachylobane: potent mechanism-based inhibitors of recombinant ent-kaurene synthase from Arabidopsis thaliana. J Am Chem Soc 2007; 129:12453-60. [PMID: 17892288 PMCID: PMC3714097 DOI: 10.1021/ja072447e] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The secondary ent-beyeran-16-yl carbocation (7) is a key branch point intermediate in mechanistic schemes to rationalize the cyclic structures of many tetra- and pentacyclic diterpenes, including ent-beyerene, ent-kaurene, ent-trachylobane, and ent-atiserene, presumed precursors to >1000 known diterpenes. To evaluate these mechanistic hypotheses, we synthesized the heterocyclic analogues 16-aza-ent-beyerane (12) and 16-aza-ent-trachylobane (13) by means of Hg(II)- and Pb(IV)-induced cyclizations onto the Delta12 double bonds of tricyclic intermediates bearing carbamoylmethyl and aminomethyl groups at C-8. The 13,16-seco-16-norcarbamate (20a) was obtained from ent-beyeran-16-one oxime (17) by Beckmann fragmentation, hydrolysis, and Curtius rearrangement. The aza analogues inhibited recombinant ent-kaurene synthase from Arabidopsis thaliana (GST-rAtKS) with inhibition constants (IC50 = 1 x 10-7 and 1 x 10-6 M) similar in magnitude to the pseudo-binding constant of the bicyclic ent-copalyl diphosphate substrate (Km = 3 x 10-7 M). Large enhancements of binding affinities (IC50 = 4 x 10-9 and 2 x 10-8 M) were observed in the presence of 1 mM pyrophosphate, which is consistent with a tightly bound ent-beyeranyl+/pyrophosphate- ion pair intermediate in the cyclization-rearrangement catalyzed by this diterpene synthase. The weak inhibition (IC50 = 1 x 10-5 M) exhibited by ent-beyeran-16-exo-yl diphosphate (11) and its failure to undergo bridge rearrangement to kaurene appear to rule out the covalent diphosphate as a free intermediate. 16-Aza-ent-beyerane is proposed as an effective mimic for the ent-beyeran-16-yl carbocation with potential applications as an active site probe for the various ent-diterpene cyclases and as a novel, selective inhibitor of gibberellin biosynthesis in plants.
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Affiliation(s)
- Arnab Roy
- Albany Molecular Sciences, Hyderabad, India
- Department of Chemistry University of Illinois, 600 South Mathews Avenue Urbana, IL 61801
| | - Frank G. Roberts
- Department of Chemistry, University of Chicago, Chicago, IL
- Department of Chemistry University of Illinois, 600 South Mathews Avenue Urbana, IL 61801
| | - P. Ross Wilderman
- Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA 50011
| | - Ke Zhou
- Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA 50011
| | - Reuben J. Peters
- Department of Biochemistry, Biophysics, & Molecular Biology, Iowa State University, Ames, IA 50011
| | - Robert M. Coates
- Department of Chemistry University of Illinois, 600 South Mathews Avenue Urbana, IL 61801
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203
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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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204
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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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205
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Landmann C, Fink B, Festner M, Dregus M, Engel KH, Schwab W. Cloning and functional characterization of three terpene synthases from lavender (Lavandula angustifolia). Arch Biochem Biophys 2007; 465:417-29. [PMID: 17662687 DOI: 10.1016/j.abb.2007.06.011] [Citation(s) in RCA: 114] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2007] [Revised: 06/18/2007] [Accepted: 06/19/2007] [Indexed: 12/01/2022]
Abstract
The essential oil of lavender (Lavandula angustifolia) is mainly composed of mono- and sesquiterpenes. Using a homology-based PCR strategy, two monoterpene synthases (LaLIMS and LaLINS) and one sesquiterpene synthase (LaBERS) were cloned from lavender leaves and flowers. LaLIMS catalyzed the formation of (R)-(+)-limonene, terpinolene, (1R,5S)-(+)-camphene, (1R,5R)-(+)-alpha-pinene, beta-myrcene and traces of alpha-phellandrene. The proportions of these products changed significantly when Mn(2+) was supplied as the cofactor instead of Mg(2+). The second enzyme LaLINS produced exclusively (R)-(-)-linalool, the main component of lavender essential oil. LaBERS transformed farnesyl diphosphate and represents the first reported trans-alpha-bergamotene synthase. It accepted geranyl diphosphate with higher affinity than farnesyl diphosphate and also produced monoterpenes, albeit at low rates. LaBERS is probably derived from a parental monoterpene synthase by the loss of the plastidial signal peptide and by broadening its substrate acceptance spectrum. The identification and description of the first terpene synthases from L. angustifolia forms the basis for the biotechnological modification of essential oil composition in lavender.
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Affiliation(s)
- Christian Landmann
- Biomolecular Food Technology, Technical University Munich, Lise-Meitner-Str. 34, 85354 Freising, Germany
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206
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van Schie CCN, Haring MA, Schuurink RC. Tomato linalool synthase is induced in trichomes by jasmonic acid. PLANT MOLECULAR BIOLOGY 2007; 64:251-63. [PMID: 17440821 PMCID: PMC1876254 DOI: 10.1007/s11103-007-9149-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/13/2006] [Accepted: 02/08/2007] [Indexed: 05/14/2023]
Abstract
Tomato (Lycopersicon esculentum) plants emit a blend of volatile organic compounds, which mainly consists of terpenes. Upon herbivory or wounding, the emission of several terpenes increases. We have identified and characterized the first two tomato monoterpene synthases, LeMTS1 and LeMTS2. Although these proteins were highly homologous, recombinant LeMTS1 protein produced (R)-linalool from geranyl diphosphate (GPP) and (E)-nerolidol from farnesyl diphosphate (FPP), while recombinant LeMTS2 produced beta-phellandrene, beta-myrcene, and sabinene from GPP. In addition, these genes were expressed in different tissues: LeMTS1 was expressed in flowers, young leaves, stems, and petioles, while LeMTS2 was strongest expressed in stems and roots. LeMTS1 expression in leaves was induced by spider mite-infestation, wounding and jasmonic acid (JA)-treatment, while LeMTS2 did not respond to these stimuli. The expression of LeMTS1 in stems and petioles was predominantly detected in trichomes and could be induced by JA. Because JA treatment strongly induced emission of linalool and overexpression of LeMTS1 in tomato resulted in increased production of linalool, we propose that LeMTS1 is a genuine linalool synthase. Our results underline the importance of trichomes in JA-induced terpene emission in tomato.
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Affiliation(s)
- Chris C. N. van Schie
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, 1098 SM Amsterdam, The Netherlands
| | - Michel A. Haring
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, 1098 SM Amsterdam, The Netherlands
| | - Robert C. Schuurink
- Swammerdam Institute for Life Sciences, Department of Plant Physiology, University of Amsterdam, 1098 SM Amsterdam, The Netherlands
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207
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Kampranis SC, Ioannidis D, Purvis A, Mahrez W, Ninga E, Katerelos NA, Anssour S, Dunwell JM, Degenhardt J, Makris AM, Goodenough PW, Johnson CB. Rational conversion of substrate and product specificity in a Salvia monoterpene synthase: structural insights into the evolution of terpene synthase function. THE PLANT CELL 2007; 19:1994-2005. [PMID: 17557809 PMCID: PMC1955729 DOI: 10.1105/tpc.106.047779] [Citation(s) in RCA: 168] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Terpene synthases are responsible for the biosynthesis of the complex chemical defense arsenal of plants and microorganisms. How do these enzymes, which all appear to share a common terpene synthase fold, specify the many different products made almost entirely from one of only three substrates? Elucidation of the structure of 1,8-cineole synthase from Salvia fruticosa (Sf-CinS1) combined with analysis of functional and phylogenetic relationships of enzymes within Salvia species identified active-site residues responsible for product specificity. Thus, Sf-CinS1 was successfully converted to a sabinene synthase with a minimum number of rationally predicted substitutions, while identification of the Asn side chain essential for water activation introduced 1,8-cineole and alpha-terpineol activity to Salvia pomifera sabinene synthase. A major contribution to product specificity in Sf-CinS1 appears to come from a local deformation within one of the helices forming the active site. This deformation is observed in all other mono- or sesquiterpene structures available, pointing to a conserved mechanism. Moreover, a single amino acid substitution enlarged the active-site cavity enough to accommodate the larger farnesyl pyrophosphate substrate and led to the efficient synthesis of sesquiterpenes, while alternate single substitutions of this critical amino acid yielded five additional terpene synthases.
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Affiliation(s)
- Sotirios C Kampranis
- Department of Natural Products and Biotechnology, Mediterranean Agronomic Institute of Chania, Chania, Greece.
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208
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Xu M, Wilderman PR, Peters RJ. Following evolution's lead to a single residue switch for diterpene synthase product outcome. Proc Natl Acad Sci U S A 2007; 104:7397-401. [PMID: 17456599 PMCID: PMC1855280 DOI: 10.1073/pnas.0611454104] [Citation(s) in RCA: 131] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2006] [Indexed: 11/18/2022] Open
Abstract
There have been few insights into the biochemical origins of natural product biosynthesis from primary metabolism. Of particular interest are terpene synthases, which often mediate the committed step in particular biosynthetic pathways so that alteration of their product outcome is a key step in the derivation of novel natural products. These enzymes also catalyze complex reactions of significant mechanistic interest. Following an evolutionary lead from two recently diverged, functionally distinct diterpene synthase orthologs from different subspecies of rice, we have identified a single residue that can switch product outcome. Specifically, the mutation of a conserved isoleucine to threonine that acts to convert not only the originally targeted isokaurene synthase into a specific pimaradiene synthase but also has a much broader effect, which includes conversion of the ent-kaurene synthases found in all higher plants for gibberellin phytohormone biosynthesis to the production of pimaradiene. This surprisingly facile switch for diterpene synthase catalytic specificity indicates the ease with which primary (gibberellin) metabolism can be subverted to secondary biosynthesis and may underlie the widespread occurrence of pimaradiene-derived natural products. In addition, because this isoleucine is required for the mechanistically more complex cyclization to tetracyclic kaurene, whereas substitution with threonine "short-circuits" this mechanism to produce the "simpler" tricyclic pimaradiene, our results have some implications regarding the means by which terpene synthases specify product outcome.
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Affiliation(s)
- Meimei Xu
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011
| | - P. Ross Wilderman
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011
| | - Reuben J. Peters
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011
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209
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Affiliation(s)
- David W Christianson
- Roy and Diana Vagelos Laboratories, Department of Chemistry, University of Pennsylvania, Philadelphia, PA 19104, USA.
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210
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Hyatt DC, Youn B, Zhao Y, Santhamma B, Coates RM, Croteau RB, Kang C. Structure of limonene synthase, a simple model for terpenoid cyclase catalysis. Proc Natl Acad Sci U S A 2007; 104:5360-5. [PMID: 17372193 PMCID: PMC1838495 DOI: 10.1073/pnas.0700915104] [Citation(s) in RCA: 159] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
The crystal structure of (4S)-limonene synthase from Mentha spic ata, a metal ion-dependent monoterpene cyclase that catalyzes the coupled isomerization and cyclization of geranyl diphosphate, is reported at 2.7-A; resolution in two forms liganded to the substrate and intermediate analogs, 2-fluorogeranyl diphosphate and 2-fluorolinalyl diphosphate, respectively. The implications of these findings are described for domain interactions in the homodimer and for changes in diphosphate-metal ion coordination and substrate binding conformation in the course of the multistep reaction.
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Affiliation(s)
- David C. Hyatt
- *Institute of Biological Chemistry, Washingston State University, Pullman, WA 99164-6340
| | - Buhyun Youn
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164-4660; and
| | - Yuxin Zhao
- Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, IL 61801
| | - Bindu Santhamma
- Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, IL 61801
| | - Robert M. Coates
- Department of Chemistry, University of Illinois at Urbana–Champaign, Urbana, IL 61801
| | - Rodney B. Croteau
- *Institute of Biological Chemistry, Washingston State University, Pullman, WA 99164-6340
- To whom correspondence may be addressed. E-mail: or
| | - ChulHee Kang
- School of Molecular Biosciences, Washington State University, Pullman, WA 99164-4660; and
- To whom correspondence may be addressed. E-mail: or
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211
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Xu M, Wilderman PR, Morrone D, Xu J, Roy A, Margis-Pinheiro M, Upadhyaya NM, Coates RM, Peters RJ. Functional characterization of the rice kaurene synthase-like gene family. PHYTOCHEMISTRY 2007; 68:312-26. [PMID: 17141283 DOI: 10.1016/j.phytochem.2006.10.016] [Citation(s) in RCA: 94] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2006] [Revised: 09/25/2006] [Accepted: 10/20/2006] [Indexed: 05/09/2023]
Abstract
The rice (Oryza sativa) genome contains a family of kaurene synthase-like genes (OsKSL) presumably involved in diterpenoid biosynthesis. While a number of OsKSL enzymes have been functionally characterized, several have not been previously investigated, and the gene family has not been broadly analyzed. Here we report cloning of several OsKSL genes and functional characterization of the encoded enzymes. In particular, we have verified the expected production of ent-kaur-16-ene by the gibberellin phytohormone biosynthesis associated OsKS1 and demonstrated that OsKSL3 is a pseudo-gene, while OsKSL5 and OsKSL6 produce ent-(iso)kaur-15-ene. Similar to previous reports, we found that our sub-species variant of OsKSL7 produces ent-cassa-12,15-diene, OsKSL10 produces ent-(sandaraco)pimar-8(14),15-diene, and OsKSL8 largely syn-stemar-13-ene, although we also identified syn-stemod-12-ene as an alternative product formed in approximately 20% of the reactions catalyzed by OsKSL8. Along with our previous reports identifying OsKSL4 as a syn-pimara-7,15-diene synthase and OsKSL11 as a syn-stemod-13(17)-ene synthase, this essentially completes biochemical characterization of the OsKSL gene family, enabling broader analyses. For example, because several OsKSL enzymes are involved in phytoalexin biosynthesis and their gene transcription is inducible, promoter analysis was used to identify a pair of specifically conserved motifs that may be involved in transcriptional up-regulation during the rice plant defense response. Also examined is the continuing process of gene evolution in the OsKSL gene family, which is particularly interesting in the context of very recently reported data indicating that a japonica sub-species variant of OsKSL5 produces ent-pimara-8(14),15-diene, rather than the ent-(iso)kaur-15-ene produced by the indica sub-species variant analyzed here.
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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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212
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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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213
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Green S, Friel EN, Matich A, Beuning LL, Cooney JM, Rowan DD, MacRae E. Unusual features of a recombinant apple alpha-farnesene synthase. PHYTOCHEMISTRY 2007; 68:176-88. [PMID: 17140613 DOI: 10.1016/j.phytochem.2006.10.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2006] [Revised: 10/18/2006] [Accepted: 10/19/2006] [Indexed: 05/06/2023]
Abstract
A recombinant alpha-farnesene synthase from apple (Malus x domestica), expressed in Escherichia coli, showed features not previously reported. Activity was enhanced 5-fold by K(+) and all four isomers of alpha-farnesene, as well as beta-farnesene, were produced from an isomeric mixture of farnesyl diphosphate (FDP). Monoterpenes, linalool, (Z)- and (E)-beta-ocimene and beta-myrcene, were synthesised from geranyl diphosphate (GDP), but at 18% of the optimised rate for alpha-farnesene synthesis from FDP. Addition of K(+) reduced monoterpene synthase activity. The enzyme also produced alpha-farnesene by a reaction involving coupling of GDP and isoprenyl diphosphate but at <1% of the rate with FDP. Mutagenesis of active site aspartate residues removed sesquiterpene, monoterpene and prenyltransferase activities suggesting catalysis through the same active site. Phylogenetic analysis clusters this enzyme with isoprene synthases rather than with other sesquiterpene synthases, suggesting that it has evolved differently from other plant sesquiterpene synthases. This is the first demonstration of a sesquiterpene synthase possessing prenyltransferase activity.
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Affiliation(s)
- Sol Green
- HortResearch, Mt Albert Research Centre, Horticultural and Food Research Institute of New Zealand, Private Bag 92169, Auckland, New Zealand.
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214
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Luan F, Degenhardt A, Mosandl A, Wüst M. Mechanism of wine lactone formation: demonstration of stereoselective cyclization and 1,3-hydride shift. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2006; 54:10245-52. [PMID: 17177567 DOI: 10.1021/jf0625306] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
The cyclization mechanism of (E)-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid to wine lactone under acidic aqueous conditions was investigated using the two stereoselectively deuterium-labeled precursors (2E,6R,7Z)-[8-2H]-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid and (2E,7E)-(+/-)-[8-2H]-2,6-dimethyl-6-hydroxyocta-2,7-dienoic acid. A detailed analysis of the generated wine lactone isomers by enantioselective multidimensional gas chromatography (MDGC)/ion trap tandem mass spectrometry demonstrates that the formation of wine lactone proceeds via a nonenzymatic stereoselective cationic cyclization cascade that includes a 1,3-hydride shift. Usually, such mechanisms are features of cyclization reactions that are catalyzed by terpene cyclases. This nonenzymatic conversion of an acyclic precursor to a bicyclic monoterpene under relevant cationic cyclization conditions has rarely been observed and confirms recent suggestions that the precursor itself can provide the chemical functionality required for specific steps in the cyclization cascade.
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Affiliation(s)
- Fang Luan
- Institut für Lebensmittelchemie, Johann Wolfgang Goethe-Universität Frankfurt am Main, Max-von-Laue-Strasse 9, D-60438 Frankfurt (Main), Germany
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215
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Deguerry F, Pastore L, Wu S, Clark A, Chappell J, Schalk M. The diverse sesquiterpene profile of patchouli, Pogostemon cablin, is correlated with a limited number of sesquiterpene synthases. Arch Biochem Biophys 2006; 454:123-36. [PMID: 16970904 DOI: 10.1016/j.abb.2006.08.006] [Citation(s) in RCA: 110] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2006] [Revised: 08/02/2006] [Accepted: 08/03/2006] [Indexed: 11/21/2022]
Abstract
Pogostemon cablin (patchouli), like many plants within the Lamiaceae, accumulates large amounts of essential oil. Patchouli oil is unique because it consists of over 24 different sesquiterpenes, rather than a blend of different mono-, sesqui- and di-terpene compounds. To determine if this complex mixture of sesquiterpenes arises from an equal number of unique sesquiterpene synthases, we developed a RT-PCR strategy to isolate and functionally characterize the respective patchouli oil synthase genes. Unexpectedly, only five terpene synthase cDNA genes were isolated. Four of the cDNAs encode for synthases catalyzing the biosynthesis of one major sesquiterpene, including a gamma-curcumene synthase, two germacrene D synthases, and a germacrene A synthase. The fifth cDNA encodes for a patchoulol synthase, which catalyzes the conversion of FPP to patchoulol plus at least 13 additional sesquiterpene products. Equally intriguing, the yield of the different in vitro reaction products resembles quantitatively and qualitatively the profile of sesquiterpenes found in patchouli oil extracted from plants, suggesting that a single terpene synthase is responsible for the bulk and diversity of terpene products produced in planta.
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Affiliation(s)
- Fabienne Deguerry
- Firmenich SA, Biotechnology Department, Corporate R and D Division, P.O. Box 239, CH-1211 Geneva 8, Switzerland
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216
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Tholl D. Terpene synthases and the regulation, diversity and biological roles of terpene metabolism. CURRENT OPINION IN PLANT BIOLOGY 2006; 9:297-304. [PMID: 16600670 DOI: 10.1016/j.pbi.2006.03.014] [Citation(s) in RCA: 449] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2006] [Accepted: 03/22/2006] [Indexed: 05/08/2023]
Abstract
Terpene synthases are the primary enzymes in the formation of low-molecular-weight terpene metabolites. Rapid progress in the biochemical and molecular analysis of terpene synthases has allowed significant investigations of their evolution, structural and mechanistic properties, and regulation. The organization of terpene synthases in large gene families, their characteristic ability to form multiple products, and their spatial and temporal regulation during development and in response to biotic and abiotic factors contribute to the time-variable formation of a diverse group of terpene metabolites. The structural diversity and complexity of terpenes generates an enormous potential for mediating plant-environment interactions. Engineering the activities of terpene synthases provides opportunities for detailed functional evaluations of terpene metabolites in planta.
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Affiliation(s)
- Dorothea Tholl
- Department of Biological Sciences, Fralin Biotechnology Center, Virginia Tech University, Blacksburg, VA 24061, USA.
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217
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Abstract
Computed [B3LYP/6-31+G(d,p) and MP2/6-31+G(d,p)] structures and binding energies for complexes of nonclassical cations (carbonium ions) with ammonia, in the gas phase and several solvents, are described. Overall, nonclassical cations are found to be competent C-H hydrogen bond donors. The potential relevance of the C-H...N interactions holding the carbocation.amine complexes together for enzyme-catalyzed terpenoid synthesis is discussed.
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Affiliation(s)
- Mihaela D Bojin
- Department of Chemistry, University of California, Davis, One Shields Avenue, 95616, USA
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218
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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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219
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Keeling CI, Bohlmann J. Genes, enzymes and chemicals of terpenoid diversity in the constitutive and induced defence of conifers against insects and pathogens. THE NEW PHYTOLOGIST 2006; 170:657-75. [PMID: 16684230 DOI: 10.1111/j.1469-8137.2006.01716.x] [Citation(s) in RCA: 366] [Impact Index Per Article: 20.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Insects select their hosts, but trees cannot select which herbivores will feed upon them. Thus, as long-lived stationary organisms, conifers must resist the onslaught of varying and multiple attackers over their lifetime. Arguably, the greatest threats to conifers are herbivorous insects and their associated pathogens. Insects such as bark beetles, stem- and wood-boring insects, shoot-feeding weevils, and foliage-feeding budworms and sawflies are among the most devastating pests of conifer forests. Conifer trees produce a great diversity of compounds, such as an enormous array of terpenoids and phenolics, that may impart resistance to a variety of herbivores and microorganisms. Insects have evolved to specialize in resistance to these chemicals -- choosing, feeding upon, and colonizing hosts they perceive to be best suited to reproduction. This review focuses on the plant-insect interactions mediated by conifer-produced terpenoids. To understand the role of terpenoids in conifer-insect interactions, we must understand how conifers produce the wide diversity of terpenoids, as well as understand how these specific compounds affect insect behaviour and physiology. This review examines what chemicals are produced, the genes and proteins involved in their biosynthesis, how they work, and how they are regulated. It also examines how insects and their associated pathogens interact with, elicit, and are affected by conifer-produced terpenoids.
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Affiliation(s)
- Christopher I Keeling
- Michael Smith Laboratories, 301-2185 East Mall, University of British Columbia, Vancouver, BC V6T 1Z4, Canada
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220
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Köllner TG, O'Maille PE, Gatto N, Boland W, Gershenzon J, Degenhardt J. Two pockets in the active site of maize sesquiterpene synthase TPS4 carry out sequential parts of the reaction scheme resulting in multiple products. Arch Biochem Biophys 2005; 448:83-92. [PMID: 16297849 DOI: 10.1016/j.abb.2005.10.011] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2005] [Revised: 10/12/2005] [Accepted: 10/13/2005] [Indexed: 11/19/2022]
Abstract
One of the most interesting features of terpene synthases is their ability to form multiple products with different carbon skeletons from a single prenyl diphosphate substrate. The maize sesquiterpene synthase TPS4, for example, produces a mixture of 14 different olefinic sesquiterpenes. To understand the complex TPS4 reaction mechanism, we modeled the active site cavity and conducted docking simulations with the substrate farnesyl diphosphate, several predicted carbocation intermediates, and the final reaction products. The model suggests that discrete steps of the reaction sequence are controlled by two different active site pockets, with the conformational change of the bisabolyl cation intermediate causing a shift from one pocket to the other. Site-directed mutagenesis and measurements of mutant activity in the presence of (E,E)- and (Z,E)-farnesyl diphosphate as substrates were employed to test this model. Amino acid alterations in pocket I indicated that early steps of the catalytic process up to the formation of the monocyclic bisabolyl cation are probably localized in this compartment. Mutations in pocket II primarily inhibited the formation of bicylic compounds, suggesting that secondary cyclizations of the bisabolyl cation are catalyzed in pocket II.
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Affiliation(s)
- Tobias G Köllner
- Max Planck Institute for Chemical Ecology, Hans-Knöll Strasse 8, D-07745 Jena, Germany
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221
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Morrone D, Jin Y, Xu M, Choi SY, Coates RM, Peters RJ. An unexpected diterpene cyclase from rice: functional identification of a stemodene synthase. Arch Biochem Biophys 2005; 448:133-40. [PMID: 16256063 DOI: 10.1016/j.abb.2005.09.001] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2005] [Revised: 09/13/2005] [Accepted: 09/14/2005] [Indexed: 11/27/2022]
Abstract
We have cloned a novel diterpene synthase (OsKSL11) from rice that produces stemod-13(17)-ene from syn-copalyl diphosphate. Notably, this gene sequence was not predicted from the extensive sequence information available for rice, nor, despite extensive phytochemical investigations, has this diterpene or any derived natural product previously been reported in rice plants. OsKSL11 represents the first identified stemodene synthase, which catalyzes the committed step in biosynthesis of the stemodane family of diterpenoid natural products, some of which possess antiviral activity. In addition, OsKSL11 is highly homologous to the mechanistically similar stemarene synthase recently identified from rice, making this pair of diterpene cyclases an excellent model system for investigating the enzymatic determinants for differential product outcome. The unexpected nature of this cyclase and its product parallels recent observations of previously unrecognized natural products metabolism in Arabidopsis thaliana, suggesting that many, if not all, plant species will prove to have extensive biosynthetic capacity.
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Affiliation(s)
- Dana Morrone
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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222
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Abstract
Wherein we learn that when working with plant terpene synthases, sometimes it is not the isotopes that get scrambled.
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Affiliation(s)
- David E Cane
- Department of Chemistry, Box H, Brown University, Providence, RI 02912-9108, USA.
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223
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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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224
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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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225
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Sharkey TD, Yeh S, Wiberley AE, Falbel TG, Gong D, Fernandez DE. Evolution of the isoprene biosynthetic pathway in kudzu. PLANT PHYSIOLOGY 2005; 137:700-12. [PMID: 15653811 PMCID: PMC1065370 DOI: 10.1104/pp.104.054445] [Citation(s) in RCA: 122] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/05/2004] [Revised: 11/05/2004] [Accepted: 11/08/2004] [Indexed: 05/19/2023]
Abstract
Isoprene synthase converts dimethylallyl diphosphate, derived from the methylerythritol 4-phosphate (MEP) pathway, to isoprene. Isoprene is made by some plants in substantial amounts, which affects atmospheric chemistry, while other plants make no isoprene. As part of our long-term study of isoprene synthesis, the genetics of the isoprene biosynthetic pathway of the isoprene emitter, kudzu (Pueraria montana), was compared with similar genes in Arabidopsis (Arabidopsis thaliana), which does not make isoprene. The MEP pathway genes in kudzu were similar to the corresponding Arabidopsis genes. Isoprene synthase genes of kudzu and aspen (Populus tremuloides) were cloned to compare their divergence with the divergence seen in MEP pathway genes. Phylogenetic analysis of the terpene synthase gene family indicated that isoprene synthases are either within the monoterpene synthase clade or sister to it. In Arabidopsis, the gene most similar to isoprene synthase is a myrcene/ocimene (acyclic monoterpenes) synthase. Two phenylalanine residues found exclusively in isoprene synthases make the active site smaller than other terpene synthase enzymes, possibly conferring specificity for the five-carbon substrate rather than precursors of the larger isoprenoids. Expression of the kudzu isoprene synthase gene in Arabidopsis caused Arabidopsis to emit isoprene, indicating that whether or not a plant emits isoprene depends on whether or not it has a terpene synthase capable of using dimethylallyl diphosphate.
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Affiliation(s)
- Thomas D Sharkey
- Department of Botany, University of Wisconsin, Madison, Wisconsin 53706, USA.
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226
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Abstract
Natural products have inspired chemists and physicians for millennia. Their rich structural diversity and complexity has prompted synthetic chemists to produce them in the laboratory, often with therapeutic applications in mind, and many drugs used today are natural products or natural-product derivatives. Recent years have seen considerable advances in our understanding of natural-product biosynthesis. Coupled with improvements in approaches for natural-product isolation, characterization and synthesis, these could be opening the door to a new era in the investigation of natural products in academia and industry.
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Affiliation(s)
- Jon Clardy
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, USA.
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227
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Tokiwano T, Endo T, Tsukagoshi T, Goto H, Fukushi E, Oikawa H. Proposed mechanism for diterpene synthases in the formation of phomactatriene and taxadiene. Org Biomol Chem 2005; 3:2713-22. [PMID: 16032349 DOI: 10.1039/b506411b] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To obtain insight into how the cyclization pathway is controlled, the mechanism of diterpene synthase reactions (the putative phomactatriene synthase and taxadiene synthases) involving the same intermediate was investigated in detail. The mechanism of the initial transformation of GGDP to verticillen-12-yl cation (A+) was proposed based on the labelling pattern of phomactatriene (9a) obtained in the feeding experiments with 13C-labelled acetates. To obtain information on the reaction pathway of A+ to 9a and taxadiene, reactions of verticillol with various acids were conducted. Structural determination of products allowed us to propose a reaction pathway via cations A+, D+, E+, F+ and G+. Identification of hydrocarbons in mycelial extracts of phomactin-producing fungus supported the proposed reaction mechanism. Based on the results of ab initio calculations for highly flexible cation intermediates, a mechanism is proposed.
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Affiliation(s)
- Tetsuo Tokiwano
- Division of Chemistry, Graduate School of Science, Hokkaido University, Sapporo 060-0810, Japan
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228
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Molecular Biochemistry and Genomics of Terpenoid Defenses in Conifers. RECENT ADVANCES IN PHYTOCHEMISTRY 2005. [DOI: 10.1016/s0079-9920(05)80003-6] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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229
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Lücker J, Bowen P, Bohlmann J. Vitis vinifera terpenoid cyclases: functional identification of two sesquiterpene synthase cDNAs encoding (+)-valencene synthase and (-)-germacrene D synthase and expression of mono- and sesquiterpene synthases in grapevine flowers and berries. PHYTOCHEMISTRY 2004; 65:2649-59. [PMID: 15464152 DOI: 10.1016/j.phytochem.2004.08.017] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Revised: 07/21/2004] [Indexed: 05/04/2023]
Abstract
Valencene is a volatile sesquiterpene emitted from flowers of grapevine, Vitis vinifera L. A full-length cDNA from the cultivar Gewürztraminer was functionally expressed in Escherichia coli and found to encode valencene synthase (VvVal). The two major products formed by recombinant VvVal enzyme activity with farnesyl diphosphate (FPP) as substrate are (+)-valencene and (-)-7-epi-alpha-selinene. Grapevine valencene synthase is closely related to a second sesquiterpene synthase from this species, (-)-germacrene D synthase (VvGerD). VvVal and VvGerD cDNA probes revealed strong signals in Northern hybridizations with RNA isolated from grapevine flower buds. Transcript levels were lower in open pre-anthesis flowers, flowers after anthesis, or at early onset of fruit development. Similar results were obtained using a third probe, (-)-alpha-terpineol synthase, a monoterpenol synthase. Sesquiterpene synthase and monoterpene synthase transcripts were not detected in the mesocarp and exocarp during early stages of fruit development, but transcripts hybridizing with VvVal appeared during late ripening of the berries. Sesquiterpene synthase transcripts were also detected in young seeds.
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Affiliation(s)
- Joost Lücker
- Biotechnology Laboratory, Department of Botany, University of British Columbia, 6174 University Boulevard, Vancouver, BC, V6T 1Z3, Canada
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230
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Wilderman PR, Xu M, Jin Y, Coates RM, Peters RJ. Identification of syn-pimara-7,15-diene synthase reveals functional clustering of terpene synthases involved in rice phytoalexin/allelochemical biosynthesis. PLANT PHYSIOLOGY 2004; 135:2098-105. [PMID: 15299118 PMCID: PMC520781 DOI: 10.1104/pp.104.045971] [Citation(s) in RCA: 146] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Rice (Oryza sativa) produces momilactone diterpenoids as both phytoalexins and allelochemicals. Accordingly, the committed step in biosynthesis of these natural products is catalyzed by the class I terpene synthase that converts syn-copalyl diphosphate to the corresponding polycyclic hydrocarbon intermediate syn-pimara-7,15-diene. Here, a functional genomics approach was utilized to identify a syn-copalyl diphosphate specific 9beta-pimara-7,15-diene synthase (OsDTS2). To our knowledge, this is the first identified terpene synthase with this particular substrate stereoselectivity and, by comparison with the previously described and closely related ent-copalyl diphosphate specific cassa-12,15-diene synthase (OsDTC1), provides a model system for investigating the enzymatic determinants underlying the observed difference in substrate specificity. Further, OsDTS2 mRNA in leaves is up-regulated by conditions that stimulate phytoalexin biosynthesis but is constitutively expressed in roots, where momilactones are constantly synthesized as allelochemicals. Therefore, transcription of OsDTS2 seems to be an important regulatory point for controlling production of these defensive compounds. Finally, the gene identified here as OsDTS2 has previously been mapped at 14.3 cM on chromosome 4. The class II terpene synthase producing syn-copalyl diphosphate from the universal diterpenoid precursor geranylgeranyl diphosphate was also mapped to this same region. These genes catalyze sequential cyclization steps in momilactone biosynthesis and seem to have been evolutionarily coupled by physical linkage and resulting cosegregation. Further, the observed correlation between physical proximity and common metabolic function indicates that other such class I and class II terpene synthase gene clusters may similarly catalyze consecutive reactions in shared biosynthetic pathways.
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Affiliation(s)
- P Ross Wilderman
- Department of Biochemistry, Biophysics, and Molecular Biology, Iowa State University, Ames, IA 50011, USA
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231
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Dudareva N, Pichersky E, Gershenzon J. Biochemistry of plant volatiles. PLANT PHYSIOLOGY 2004; 135:1893-902. [PMID: 15326281 PMCID: PMC520761 DOI: 10.1104/pp.104.049981] [Citation(s) in RCA: 498] [Impact Index Per Article: 24.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2004] [Revised: 07/19/2004] [Accepted: 07/19/2004] [Indexed: 05/17/2023]
Affiliation(s)
- Natalia Dudareva
- Department of Horticulture and Landscape Architecture, Purdue University, West Lafayette, IN 47907, USA.
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232
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Martin DM, Fäldt J, Bohlmann J. Functional characterization of nine Norway Spruce TPS genes and evolution of gymnosperm terpene synthases of the TPS-d subfamily. PLANT PHYSIOLOGY 2004; 135:1908-27. [PMID: 15310829 PMCID: PMC520763 DOI: 10.1104/pp.104.042028] [Citation(s) in RCA: 252] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Constitutive and induced terpenoids are important defense compounds for many plants against potential herbivores and pathogens. In Norway spruce (Picea abies L. Karst), treatment with methyl jasmonate induces complex chemical and biochemical terpenoid defense responses associated with traumatic resin duct development in stems and volatile terpenoid emissions in needles. The cloning of (+)-3-carene synthase was the first step in characterizing this system at the molecular genetic level. Here we report the isolation and functional characterization of nine additional terpene synthase (TPS) cDNAs from Norway spruce. These cDNAs encode four monoterpene synthases, myrcene synthase, (-)-limonene synthase, (-)-alpha/beta-pinene synthase, and (-)-linalool synthase; three sesquiterpene synthases, longifolene synthase, E,E-alpha-farnesene synthase, and E-alpha-bisabolene synthase; and two diterpene synthases, isopimara-7,15-diene synthase and levopimaradiene/abietadiene synthase, each with a unique product profile. To our knowledge, genes encoding isopimara-7,15-diene synthase and longifolene synthase have not been previously described, and this linalool synthase is the first described from a gymnosperm. These functionally diverse TPS account for much of the structural diversity of constitutive and methyl jasmonate-induced terpenoids in foliage, xylem, bark, and volatile emissions from needles of Norway spruce. Phylogenetic analyses based on the inclusion of these TPS into the TPS-d subfamily revealed that functional specialization of conifer TPS occurred before speciation of Pinaceae. Furthermore, based on TPS enclaves created by distinct branching patterns, the TPS-d subfamily is divided into three groups according to sequence similarities and functional assessment. Similarities of TPS evolution in angiosperms and modeling of TPS protein structures are discussed.
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Affiliation(s)
- Diane M Martin
- Biotechnology Laboratory, University of British Columbia, Vancouver V6T 1Z3, British Columbia, Canada
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233
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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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234
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Felicetti B, Cane DE. Aristolochene Synthase: Mechanistic Analysis of Active Site Residues by Site-Directed Mutagenesis. J Am Chem Soc 2004; 126:7212-21. [PMID: 15186158 DOI: 10.1021/ja0499593] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Incubation of farnesyl diphosphate (1) with Penicillium roqueforti aristolochene synthase yielded (+)-aristolochene (4), accompanied by minor quantities of the proposed intermediate (S)-(-)germacrene A (2) and the side-product (-)-valencene (5) in a 94:4:2 ratio. By contrast, the closely related aristolochene synthase from Aspergillus terreus cyclized farnesyl diphosphate only to (+)-aristolochene (4). Site-directed mutagenesis of amino acid residues in two highly conserved Mg(2+)-binding domains led in most cases to reductions in both k(cat) and k(cat)/K(m) as well as increases in the proportion of (S)-(-)germacrene A (2), with the E252Q mutant of the P. roqueforti aristolochene synthase producing only (-)-2. The P. roqueforti D115N, N244L, and S248A/E252D mutants were inactive, as was the A. terreus mutant E227Q. The P. roqueforti mutant Y92F displayed a 100-fold reduction in k(cat) that was offset by a 50-fold decrease in K(m), resulting in a relatively minor 2-fold decrease in catalytic efficiency, k(cat)/K(m). The finding that Y92F produced (+)-aristolochene (4) as 81% of the product, accompanied by 7% 5 and 12% 2, rules out Tyr-92 as the active site Lewis acid that is responsible for protonation of the germacrene A intermediate in the formation of aristolochene (4).
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Affiliation(s)
- Brunella Felicetti
- Department of Chemistry, Box H, Brown University, Providence, Rhode Island 02912-9108, USA
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235
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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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236
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Köllner TG, Schnee C, Gershenzon J, Degenhardt J. The variability of sesquiterpenes emitted from two Zea mays cultivars is controlled by allelic variation of two terpene synthase genes encoding stereoselective multiple product enzymes. THE PLANT CELL 2004; 16:1115-31. [PMID: 15075399 PMCID: PMC423204 DOI: 10.1105/tpc.019877] [Citation(s) in RCA: 169] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2003] [Accepted: 02/16/2004] [Indexed: 05/18/2023]
Abstract
The mature leaves and husks of Zea mays release a complex blend of terpene volatiles after anthesis consisting predominantly of bisabolane-, sesquithujane-, and bergamotane-type sesquiterpenes. The varieties B73 and Delprim release the same volatile constituents but in significantly different proportions. To study the molecular genetic and biochemical mechanisms controlling terpene diversity and distribution in these varieties, we isolated the closely related terpene synthase genes terpene synthase4 (tps4) and tps5 from both varieties. The encoded enzymes, TPS4 and TPS5, each formed the same complex mixture of sesquiterpenes from the precursor farnesyl diphosphate but with different proportions of products. These mixtures correspond to the sesquiterpene blends observed in the varieties B73 and Delprim, respectively. The differences in the stereoselectivity of TPS4 and TPS5 are determined by four amino acid substitutions with the most important being a Gly instead of an Ala residue at position 409 at the catalytic site of the enzyme. Although both varieties contain tps4 and tps5 alleles, their differences in terpene composition result from the fact that B73 has only a single functional allele of tps4 and no functional alleles of tps5, whereas Delprim has only a functional allele of tps5 and no functional alleles of tps4. Lack of functionality was shown to be attributable to frame-shift mutations or amino acid substitutions that greatly reduce the activity of their encoded proteins. Therefore, the diversity of sesquiterpenes in these two maize cultivars is strongly influenced by single nucleotide changes in the alleles of two terpene synthase genes.
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Affiliation(s)
- Tobias G Köllner
- Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany
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237
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Reinert DJ, Balliano G, Schulz GE. Conversion of Squalene to the Pentacarbocyclic Hopene. ACTA ACUST UNITED AC 2004; 11:121-6. [PMID: 15113001 DOI: 10.1016/j.chembiol.2003.12.013] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2003] [Accepted: 11/06/2003] [Indexed: 10/21/2022]
Abstract
The membrane protein squalene-hopene cyclase was cocrystallized with 2-azasqualene and analyzed by X-ray diffraction to 2.13 A resolution. The conformation of this close analog was clearly established, and it agreed with the common textbook presentation. The bound squalene undergoes only small conformational changes during the formation of rings A through D, thus requiring no intermediate. However, ring E formation is hindered by an entropic barrier, which may explain its absence in the steroids. The structure analysis revealed a mobile region between the active center cavity and the membrane, which may melt, opening a passage for squalene and hopene.
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Affiliation(s)
- Dirk J Reinert
- Institut für Organische Chemie und Biochemie, Albert-Ludwigs-Universität, Albertstr. 21, D-79104 Freiburg, Germany
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238
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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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239
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Zhu X, Heine A, Monnat F, Houk KN, Janda KD, Wilson IA. Structural basis for antibody catalysis of a cationic cyclization reaction. J Mol Biol 2003; 329:69-83. [PMID: 12742019 DOI: 10.1016/s0022-2836(03)00406-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Antibody 4C6 efficiently catalyzes a cationic cyclization reaction. Crystal structures of the antibody 4C6 Fab in complex with benzoic acid and in complex with its eliciting hapten were determined to 1.30A and 2.45A resolution, respectively. These crystal structures, together with computational analysis, have elucidated a possible mechanism for the monocyclization reaction. The hapten complex revealed a combining site pocket with high shape complementarity to the hapten. This active site cleft is dominated by aromatic residues that shield the highly reactive carbocation intermediates from solvent and stabilize the carbocation intermediates through cation-pi interactions. Modeling of an acyclic olefinic sulfonate ester substrate and the transition state (TS) structures shows that the chair-like transition state is favored, and trapping by water directly produces trans-2-(dimethylphenylsilyl)-cyclohexanol, whereas the less favored boat-like transition state leads to cyclohexene. The only significant change observed upon hapten binding is a side-chain rotation of Trp(L89), which reorients to form the base of the combining site. Intriguingly, a benzoic acid molecule was sequestered in the combining site of the unliganded antibody. The 4C6 active site was compared to that observed in a previously reported tandem cyclization antibody 19A4 hapten complex. These cationic cyclization antibodies exhibit convergent structural features with terpenoid cyclases that appear to be important for catalysis.
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Affiliation(s)
- Xueyong Zhu
- Department of Molecular Biology BBC206, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA
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240
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Degenhardt J, Gershenzon J, Baldwin IT, Kessler A. Attracting friends to feast on foes: engineering terpene emission to make crop plants more attractive to herbivore enemies. Curr Opin Biotechnol 2003; 14:169-76. [PMID: 12732318 DOI: 10.1016/s0958-1669(03)00025-9] [Citation(s) in RCA: 190] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
When attacked by herbivorous insects or mites, some plant species call on other arthropods for help. They emit mixtures of volatile compounds, dominated by terpenes, to attract carnivorous arthropods that prey on or parasitise herbivores and so reduce further damage. This fascinating defence strategy offers a new, environmentally friendly approach to crop protection. Using recent advances in the biochemistry and molecular genetics of terpene biosynthesis, it should now be possible to engineer crop plants that release terpenes for attracting herbivore enemies. By introducing or selectively altering the existing rate of terpene emission and composition, plant breeders could enable attacked plants to attract enemies and reduce additional herbivory, without compromising the effectiveness of other modes of defence.
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Affiliation(s)
- Jörg Degenhardt
- Department of Biochemistry, Max Planck Institute for Chemical Ecology, Beutenberg Campus, Winzerlaer Strasse 10, D-07745, Jena, Germany.
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241
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Phillips MA, Wildung MR, Williams DC, Hyatt DC, Croteau R. cDNA isolation, functional expression, and characterization of (+)-alpha-pinene synthase and (-)-alpha-pinene synthase from loblolly pine (Pinus taeda): stereocontrol in pinene biosynthesis. Arch Biochem Biophys 2003; 411:267-76. [PMID: 12623076 DOI: 10.1016/s0003-9861(02)00746-4] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The complex mixture of monoterpenes, sesquiterpenes, and diterpenes that comprises oleoresin provides the primary defense of conifers against bark beetles and their associated fungal pathogens. Monoterpene synthases produce the turpentine fraction of oleoresin, which allows mobilization of the diterpene resin acid component (rosin) and is also toxic toward invading insects; this is particularly the case for alpha-pinene, a prominent bicyclic monoterpene of pine turpentine. The stereochemistry of alpha-pinene is a critical determinant of host defense capability and has implications for host selection, insect pheromone biosynthesis, and tritrophic-level interactions. Pines produce both enantiomers of alpha-pinene, which appear to arise through antipodal reaction mechanisms by distinct enzymes. Using a cDNA library constructed with mRNA from flushing needles of loblolly pine (Pinus taeda), we employed a homology-based cloning strategy to isolate, and confirm by functional expression, the genes encoding (+)-(3R:5R)-alpha-pinene synthase, (-)-(3S:5S)-alpha-pinene synthase, and several other terpene synthases. The pinene synthases, which produce mirror-image products, share only 66% amino acid identity (72% similarity) but are similar in general properties to other monoterpene synthases of gymnosperms. The stereochemical control of monoterpene cyclization reactions, the evolution of "antipodal" enzymes, and the implications of turpentine composition in ecological interactions are discussed.
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Affiliation(s)
- Michael A Phillips
- Institute of Biological Chemistry, Washington State University, Pullman, WA 99164-6340, USA
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