Synthesis of (+)-5-epi-aristolochene and (+)-1-deoxycapsidiol from capsidiol

Whitehead, Ian M.; Ewing, David F.; Threlfall, David R.; Cane, David E.; Prabhakaran, Panchami

doi:10.1016/0031-9422(90)85100-t

Cited by 27 publications

(28 citation statements)

References 10 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Tobacco 5-epi-aristolochene synthase (TEAS), a sesquiterpene cyclase from Nicotiana tabacum, serves as a valuable model system for understanding the chemical mechanisms of sesquiterpene biosynthesis. The major product of this enzyme, (+)-5-epi-aristolochene (13), was first identified as the cyclic precursor of the phytoalexin capsidiol, produced in response to fungal elicitation in tobacco tissue cultures [8][9][10][11]. The assigned structure of (+)-5-epiaristolochene (13) enabled the proposal of a reaction mechanism involving initial formation then protonation of a germacrene A intermediate, followed by sequential 1,2-hydride and methyl migrations on the same face of a eudesmyl carbocation intermediate A, culminating in formation of the final product (13) (Scheme 1).…”

mentioning

confidence: 99%

Biosynthetic potential of sesquiterpene synthases: Alternative products of tobacco 5-epi-aristolochene synthase

O’Maille¹,

Chappell²,

Noel³

2006

Archives of Biochemistry and Biophysics

View full text Add to dashboard Cite

Nicotiana tabacum (tobacco) 5-epi-aristolochene synthase (TEAS) serves as an useful model for understanding the enzyme mechanisms of sesquiterpene biosynthesis. Despite extensive bio-chemical and structural characterization of TEAS, a more detailed analysis of the reaction product spectrum is lacking. This study reports the discovery and quantification of several alternative sesquiterpene products generated by recombinant TEAS in the single-vial GC-MS assay. The combined use of chiral and non-polar stationary phases for gas chromatography separations proved critical for resolving the numerous sesquiterpene products of TEAS for mass spectral analysis and identification. Co-injection studies with available authentic standards from both synthetic and natural sources further corroborated the assignment of several compounds, resulting in an annotated reaction mechanism accounting for their biosynthesis. Moreover, a previously undocumented farnesyl trans-cis isomerization pathway was observed.

show abstract

mentioning

confidence: 99%

Biosynthetic potential of sesquiterpene synthases: Alternative products of tobacco 5-epi-aristolochene synthase

O’Maille¹,

Chappell²,

Noel³

2006

Archives of Biochemistry and Biophysics

View full text Add to dashboard Cite

show abstract

“…The diastereomeric sesquiterpene epi-aristolochene (4-epieremophila-9,11-diene) has been identified in tobacco (Nicotiana tabacum) (11)(12)(13) and results from the cyclization of farnesyl diphosphate by epi-aristolochene synthase ( Fig. 1) (14).…”

mentioning

confidence: 99%

Crystal Structure Determination of Aristolochene Synthase from the Blue Cheese Mold, Penicillium roqueforti*

Caruthers¹,

Kang²,

Rynkiewicz³

et al. 2000

Journal of Biological Chemistry

Self Cite

168

200

View full text Add to dashboard Cite

The 2.5-Å resolution crystal structure of recombinant aristolochene synthase from the blue cheese mold, Penicillium roqueforti, is the first of a fungal terpenoid cyclase. The structure of the enzyme reveals active site features that participate in the cyclization of the universal sesquiterpene cyclase substrate, farnesyl diphosphate, to form the bicyclic hydrocarbon aristolochene. Metal-triggered carbocation formation initiates the cyclization cascade, which proceeds through multiple complex intermediates to yield one exclusive structural and stereochemical isomer of aristolochene. Structural homology of this fungal cyclase with plant and bacterial terpenoid cyclases, despite minimal amino acid sequence identity, suggests divergence from a common, primordial ancestor in the evolution of terpene biosynthesis.Aristolochene synthase is a terpenoid cyclase from the blue cheese mold, Penicillium roqueforti, that catalyzes the metal-dependent cyclization of farnesyl diphosphate to form the bicyclic hydrocarbon aristolochene (Fig. 1) (1). Farnesyl diphosphate is the universal precursor of myriad cyclic sesquiterpenes, so each sesquiterpene cyclase plays a critical role in governing the structural and stereochemical outcome of its particular cyclization reaction. Accordingly, sesquiterpene cyclase reactions maximize product diversity starting from a minimal substrate pool, indeed, a single substrate, and the structural basis of this catalytic diversity comprises a growing question at the interface of chemistry and biology.Aristolochene synthase is a 38-kDa monomeric sesquiterpene cyclase that has been cloned (2) and overexpressed (3) in Escherichia coli. Numerous enzymological studies of P. roqueforti and Aspergillus terreus aristolochene synthases using stereospecifically labeled substrates (4 -6), a mechanism-based inhibitor (7), and the anomalous substrate (7R)-6,7-dihydrofarnesyldiphosphate (8) indicate a complex cyclization cascade proceeding through at least two discrete intermediates. Aristolochene formation is the first committed step in the biosynthesis of a large group of sesquiterpenoid fungal toxins, the most lethal of which is the novel bis-epoxide PR-toxin (4). Interestingly, the (ϩ)-enantiomer of aristolochene is generated by the fungi P. roqueforti and A. terreus, but the (Ϫ)-enantiomer is generated by the plants Aristolochia indica (9) and Bixa orella (10). Accordingly, each aristolochene synthase must provide a different template for binding the flexible polyisoprenoid substrate and subsequent intermediates in productive conformations leading to correct stereoisomer formation.The diastereomeric sesquiterpene epi-aristolochene (4-epieremophila-9,11-diene) has been identified in tobacco (Nicotiana tabacum) (11-13) and results from the cyclization of farnesyl diphosphate by epi-aristolochene synthase (Fig. 1) (14). This enzyme catalyzes the cyclization of farnesyl diphosphate by a mechanism similar in some respects to that of P. roqueforti aristolochene synthase despite only 16% amino acid sequence ident...

show abstract

“…Incorporation of [1,[2][3][4][5][6][7][8][9][10][11][12][13] C 2 ]acetate into capsidiol in Capsicum annum cultures and NMR analyses confirmed the occurrence of a methyl migration in the biosynthesis of this eremophilane sesquiterpene [6]. Retention of deuterium at C4 of capsidiol biosynthesized from [4,4-2 H 2 ]mevalonate demonstrated that the unusual trans-stereochemistry of the vicinal methyl groups could not be attributed to epimerization of a cis-eremophilane precursor [7].…”

mentioning

confidence: 88%

Stereochemistry and deuterium isotope effects associated with the cyclization-rearrangements catalyzed by tobacco epiaristolochene and hyoscyamus premnaspirodiene synthases, and the chimeric CH4 hybrid cyclase

Schenk¹,

Starks²,

Manna³

et al. 2006

Archives of Biochemistry and Biophysics

View full text Add to dashboard Cite

Tobacco epiaristolochene and hyoscyamus premnaspirodiene synthases (TEAS and HPS) catalyze the cyclizations and rearrangements of (E,E)-farnesyl diphosphate (FPP) to the corresponding bicyclic sesquiterpene hydrocarbons. The complex mechanism proceeds through a tightly bound (R)-germacrene A intermediate and involves partitioning of a common eudesm-5-yl carbocation either by angular methyl migration, or by C-9 methylene rearrangement, to form the respective eremophilane and spirovetivane structures. In this work, the stereochemistry and timing of the proton addition and elimination steps in the mechanism were investigated by synthesis of substrates bearing deuterium labels in one or both terminal methyl groups, and in the pro-S and pro-R methylene hydrogens at C-8. Incubations of the labeled FPPs with recombinant TEAS and HPS, and with the chimeric CH4 hybrid cyclase having catalytic activities of both TEAS and HPS, and of unlabeled FPP in D2O, together with gas chromatography-mass spectrometry (GC-MS) and/or NMR analyses of the labeled products gave the following results: (1) stereospecific CH3-->CH2 eliminations at the cis-terminal methyl in all cases; (2) similar primary kinetic isotope effects (KIE) of 4.25-4.64 for the CH3-->CH2 eliminations; (3) a significant intermolecular KIE (1.33+/-0.03) in competitive cyclizations of unlabeled FPP and FPP-d6 to premnaspirodiene by HPS; (4) stereoselective incorporation of label from D2O into the 1beta position of epiaristolochene; (5) stereoselective eliminations of the 1beta and 9beta protons in formation of epiaristolochene and its delta(1(10)) isomer epieremophilene by TEAS and CH4; and (6) predominant loss of the 1alpha proton in forming the cyclohexene double bond of premnaspirodiene by HPS and CH4. The results are explained by consideration of the conformations of individual intermediates, and by imposing the requirement of stereoelectronically favorable proton additions and eliminations.

show abstract

Synthesis of (+)-5-epi-aristolochene and (+)-1-deoxycapsidiol from capsidiol

Cited by 27 publications

References 10 publications

Biosynthetic potential of sesquiterpene synthases: Alternative products of tobacco 5-epi-aristolochene synthase

Biosynthetic potential of sesquiterpene synthases: Alternative products of tobacco 5-epi-aristolochene synthase

Crystal Structure Determination of Aristolochene Synthase from the Blue Cheese Mold, Penicillium roqueforti*

Stereochemistry and deuterium isotope effects associated with the cyclization-rearrangements catalyzed by tobacco epiaristolochene and hyoscyamus premnaspirodiene synthases, and the chimeric CH4 hybrid cyclase

Contact Info

Product

Resources

About