Some phosphate esters of biological importance

Tidd, B. K.

doi:10.1039/j29710001168

Cited by 20 publications

(17 citation statements)

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“…in 2 min) to zero after a lightpH 6.5 to 9.0; and to-dark transition (14). This suggests that isoprene synthase 20 …”

Section: Resultsmentioning

confidence: 75%

“…Under these conditions, the nonenzymatic reaction accounted for only a fraction of the total isoprene produced. At lower pH (c3), the nonenzymatic rate became much more significant (data not shown), indicative of acid-catalyzed solvolysis of DMAPP (20).…”

Section: Resultsmentioning

confidence: 99%

“…We the other expected product of these rea4 phosphate, using two different assay me production was detected when DMAPP N but not in enzymatic incubations. How (20), and the en-'ever, Pi production zymatic reaction might proceed through the same intermediaddition of sodium ate. Like other enzymes that use allylic diphosphates as subEyme, Pi production strates, the enzymatic reaction requires a divalent cation such f a diphosphatase in as Mg2e for maximal activity.…”

Section: Resultsmentioning

confidence: 99%

“…Mead and coworkers (5) investigated the production of isoprene in rat liver extracts, and concluded that isoprene is formed from the acid-catalyzed solvolysis of DMAPP2 (20). In this scheme, ionization of diphosphate from DMAPP would yield a transient carbocation that would give rise to isoprene as well as solvolysis products, 3-methyl-2-buten-1-ol and 2-methyl-3-buten-2-ol.…”

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confidence: 99%

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Enzymatic Synthesis of Isoprene from Dimethylallyl Diphosphate in Aspen Leaf Extracts

Silver

Fall²

1991

Plant Physiol.

183

132

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Aspen (Populus tremuloides Michx.) leaf extracts contain a newly discovered enzyme activity that catalyzes the magnesium ion-dependent elimination of diphosphate from dimethylallyl diphosphate with rearrangement to form isoprene (2-methyl,1-3-butadiene). This isoprene synthase activity has been partially purified. The nonenzymatic reaction of dimethylallyl diphosphate to isoprene, known to be acid catalyzed, may be insignificant at physiological pH. In contrast, the enzymatic reaction may be responsible for the majority of light-dependent isoprene production by isoprene-emitting plants.that isoprene is formed nonenzymatically in plant chloroplasts. In the light, the thylakoid lumen is acidified to approximately pH 5 by proton pumping (1), and if DMAPP is contained in this compartment, the acid-catalyzed reactions described above could generate isoprene. Evidence for the presence of DMAPP in the thylakoid lumen is lacking.We have been working to investigate the biochemical and physiological basis for the light-dependent formation of isoprene in plants (8, 13, 14), and as an extension of this work initiated experiments to directly test for the enzymatic production of isoprene from DMAPP. This report describes the detection of a new enzyme activity in leaf extracts that catalyzes the formation of isoprene.

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“…in 2 min) to zero after a lightpH 6.5 to 9.0; and to-dark transition (14). This suggests that isoprene synthase 20 …”

Section: Resultsmentioning

confidence: 75%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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Enzymatic Synthesis of Isoprene from Dimethylallyl Diphosphate in Aspen Leaf Extracts

Silver

Fall²

1991

Plant Physiol.

183

132

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“…1c) (11). Upon achieving a cyclization-competent substrate conformation in the closed active site, with the three negative charges of the diphosphate leaving group fully neutralized, substrate ionization (24,25) and cyclization would be initiated.…”

Section: Reactivity Of Fluorinatedmentioning

confidence: 99%

X-ray Crystallographic Studies of Substrate Binding to Aristolochene Synthase Suggest a Metal Ion Binding Sequence for Catalysis

Shishova

Miller

et al. 2008

Journal of Biological Chemistry

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Farnesyl diphosphate (FPP),2 a flexible 15-carbon isoprenoid, is the universal precursor of Ͼ300 different cyclic sesquiterpenes found in numerous plants, bacteria, and fungi (1, 2). The cyclization of FPP is catalyzed by a sesquiterpene cyclase that utilizes a trinuclear magnesium cluster to trigger the departure of the pyrophosphate (PP i ) leaving group, thereby forming an allylic carbocation that typically reacts with one of the remaining bonds of the substrate (3-7). The remarkable diversity of sesquiterpene structure and stereochemistry is the consequence of precise control exerted by the cyclase over the conformations of the flexible substrate and carbocation intermediates in the cyclization cascade.Aristolochene synthase from Aspergillus terreus is a sesquiterpene cyclase that catalyzes the cyclization of FPP to form aristolochene (Fig. 1a), the parent hydrocarbon of a large group of fungal toxins such as gigantenone, PR-toxin, and bipolaroxin (8). In contrast to aristolochene synthase from Penicillium roqueforti, which generates aristolochene predominantly (Ͼ90%) but also small amounts of germacrene A and valencene (9, 10), aristolochene synthase from A. terreus generates aristolochene exclusively (9). Each cyclase adopts the common ␣-helical fold of a class I terpenoid cyclase and contains two conserved metal binding motifs: the "aspartate-rich" motif D 90 DLLE that coordinates to Mg 3 ⅐PP i stabilizes the active site in a closed conformation that is completely sequestered from bulk solvent (Fig. 1b) (11). In addition to multiple metal coordination interactions, the PP i anion accepts hydrogen bonds from conserved residues Arg , and Tyr 315 when bound to the closed conformation (Fig. 1c). It is likely that the diphosphate group of FPP makes identical metal coordination and hydrogen bond interactions in the Michaelis complex, i.e. the complex between the enzyme and the productively bound substrate that immediately precedes the initiation of the cyclization cascade.Substrate conformation is a crucial determinant of the biosynthetic outcome of the terpenoid cyclase reaction. The active site of aristolochene synthase from A. terreus serves as a high fidelity template that fixes FPP in a single, productive conformation in the Michaelis complex; otherwise, aberrant cyclization products would result. To study the conformational control of FPP in the active site of aristolochene synthase from A. terreus, we now report the structures of crystalline complexes * This work was supported, in whole or in part, by National Institutes of Health Grants GM 56838 (to D. W. C.), GM 30301 (to D. E. C.), and GM 13956 (to R. M. C.). This work was also supported by the Engineering and Physical Sciences Research Council (Grant EP/D069580 to R. K. A.) and by Cardiff University (Studentship to F. Y.). The costs of publication of this article were defrayed in part by the payment of page charges. This article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact. Th...

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Terpenoid Cyclases: Design and Function of Electrophilic Catalysts

Cane

2007

Ciba Foundation Symposium 171 ‐ Secondary Metabolites: Their Function and Evolution

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Some phosphate esters of biological importance

Cited by 20 publications

References 0 publications

Enzymatic Synthesis of Isoprene from Dimethylallyl Diphosphate in Aspen Leaf Extracts

Enzymatic Synthesis of Isoprene from Dimethylallyl Diphosphate in Aspen Leaf Extracts

X-ray Crystallographic Studies of Substrate Binding to Aristolochene Synthase Suggest a Metal Ion Binding Sequence for Catalysis

Terpenoid Cyclases: Design and Function of Electrophilic Catalysts

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