Study of the biosynthesis of 3-isopropyl-2-methoxypyrazine produced by Pseudomonas taetrolens

Gallois, Annie; Kergomard, A.; Adda, J.

doi:10.1016/0308-8146(88)90105-7

Cited by 46 publications

(50 citation statements)

References 5 publications

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“…The OMe group could also be added in later stages if the initial condensation is performed by an amino acid instead of the methyl ester. The labeling studies by Gallois et al [12] who observed incorporation of 10, but not of glycine, and Cheng et al [13] are in accord with the biosynthetic pathway proposed in Scheme 8. The earlier proposal by Murray et al [10] suggesting the formation of methoxypyrazines by condensation of glyoxal with valine amide is a variant of our proposal and can be differentiated by 15 N-labeling studies.…”

supporting

confidence: 62%

“…Methylation during this sequence would lead to the methoxypyrazine 5 (Scheme 2). Feeding studies with labeled valine (10) and glycine (11) established the incorporation of the former into 5, but glycine (11) was not incorporated [12], possibly because it was metabolized before the pyrazine formation started [13]. To overcome this problem, feeding experiments with differently 13 C-labeled pyruvate isotopomers as metabolic precursors of glycine and valine were carried out, supporting the proposed bacterial pathway to the third class of pyrazines [13].…”

mentioning

confidence: 96%

“…-Our initial suggestion for the biosynthesis of 2 was based on the proposal by Gallois et al [12] and Cheng et al [13] (Scheme 3), starting with selfcondensation of the amino acid valine (10) to the piperazinedione 16. Compared to the proposed biosynthetic pathway to methoxypyrazines (Scheme 2), an additional reduction step is needed to remove the excess O-atom.…”

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confidence: 99%

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The Biosynthesis of Branched Dialkylpyrazines in Myxobacteria

Nawrath

Dickschat

Kunze

et al. 2010

Chemistry & Biodiversity

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The biosynthesis of the volatiles 2,5- and 2,6-diisopropylpyrazine (2 and 3, resp.) released by the myxobacteria Nannocystis exedens subsp. cinnabarina (Na c29) and Chondromyces crocatus (strains Cm c2 and Cm c5) was studied. Isotopically labeled precursors and proposed pathway intermediates were fed to agar plate cultures of the myxobacteria. Subsequently, the volatiles were collected by use of a closed loop stripping apparatus (CLSA), and incorporation into the pyrazines was followed by GC/MS analysis. [(2)H(8)]Valine was smoothly incorporated into both pyrazines clearly establishing their origin from the amino acid pool. The cyclic dipeptide valine anhydride (16)--a potential intermediate on the biosynthetic pathway to branched dialkylpyrazines--was synthesized containing (2)H(1) labels in specific positions. Feeding of [(2)H(16)]-16 and [(2)H(12)]-16 in both valine subunits mainly resulted in the formation of pyrazines derived from only one labeled amino acid, whereas only traces of the expected pyrazines with two labeled subunits were found. To investigate the origin of nitrogen in the pyrazines, a feeding experiment with [(15)N]valine was performed, resulting in the incorporation of the (15)N label. The results contradict a biosynthetic pathway via cyclic dipeptides, but rather point to a pathway on which valine is reduced to valine aldehyde. Its dimerization to 2,5-diisopropyldihydropyrazine 36 and subsequent oxidation results in 2. The proposed biosynthetic pathway neatly fits the results of earlier labeling studies and also explains the formation of the regioisomer 2,6-diisopropylpyrazine 3 by isomerization during the first condensation step of two molecules valine aldehyde. A general biosynthetic pathway to different classes of pyrazines is presented.

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supporting

confidence: 62%

mentioning

confidence: 96%

mentioning

confidence: 99%

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The Biosynthesis of Branched Dialkylpyrazines in Myxobacteria

Nawrath

Dickschat

Kunze

et al. 2010

Chemistry & Biodiversity

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“…However, feeding experiments with 13 C-labelled precursors demonstrated the incorporation of valine, but not of glycine. [11] Cheng et al used [2][3][4][5][6][7][8][9][10][11][12][13] C]pyruvate and [3-13 C]pyruvate resulting in the incorporation of the isotopic labelling in specific positions that is in accordance with a biosynthetic pathway via valine, glycine, and S-adenosylmethionine (SAM) for O-methylation. [12] The suggested pathway proceeds via a cyclic dipeptide (dioxopiperazine), O-methylation, and elimination of water, and is more plausible than any other published route (Scheme 1).…”

Section: Introductionmentioning

confidence: 98%

Pyrazine Biosynthesis in Corynebacterium glutamicum

et al. 2010

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The volatile compounds released by Corynebacterium glutamicum were collected by use of the CLSA technique (closed-loop stripping apparatus) and analysed by GC-MS. The headspace extracts contained several acyloins and pyrazines that were identified by their synthesis or comparison to commercial standards. Feeding experiments with [ 2 H 7 ]acetoin resulted in the incorporation of labelling into trimethylpyrazine and tetramethylpyrazine. Several deletion mutants targeting genes of the primary metabolism were constructed to elucidate the biosynthetic pathway to pyrazines in detail. A deletion mutant of the ketol-acid reductoisomerase was not able to convert the acetoin precursor (S)-2-acetolactate into the pathway intermediate (R)-2,3-dihy-

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“…Theoretical biosynthesis pathways have been proposed since the mid-1970s. They all start by the addition of an adicarbonyl on a branched amino acid (Leu for IBMP, Val for IPMP) to form a 2-hydroxy-3-alkylpyrazine, which is subsequently transformed into the corresponding MP, by a methoxylation reaction (Murray and Whitfield 1975;Gallois et al, 1988). While the initial addition step remains to be demonstrated in plants, an S-adenosyl-L-Met (SAM)-dependent O-methyltransferase (OMT), capable of converting 2-hydroxy-3-isobutylpyrazine (IBHP) into IBMP, has been detected in CS shoots, partially purified and sequenced (Hashizume et al, 2001a(Hashizume et al, , 2001b; Fig.…”

mentioning

confidence: 99%

Genetic Analysis of the Biosynthesis of 2-Methoxy-3-Isobutylpyrazine, a Major Grape-Derived Aroma Compound Impacting Wine Quality

et al. 2013

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Methoxypyrazines (MPs) are strongly odorant volatile molecules with vegetable-like fragrances that are widespread in plants. Some grapevine (Vitis vinifera) varieties accumulate significant amounts of MPs, including 2-methoxy-3-isobutylpyrazine (IBMP), which is the major MP in grape berries. MPs are of particular importance in white Sauvignon Blanc wines. The typicality of these wines relies on a fine balance between the pea pod, capsicum character of MPs and the passion fruit/grapefruit character due to volatile thiols. Although MPs play a crucial role in Sauvignon varietal aromas, excessive concentrations of these powerful odorants alter wine quality and reduce consumer acceptance, particularly in red wines. The last step of IBMP biosynthesis has been proposed to involve the methoxylation of the nonvolatile precursor 2-hydroxy-3-isobutylpyrazine to give rise to the highly volatile IBMP. In this work, we have used a quantitative trait loci approach to investigate the genetic bases of IBMP biosynthesis. This has led to the identification of two previously uncharacterized S-adenosyl-methionine-dependent O-methyltransferase genes, termed VvOMT3 and VvOMT4. Functional characterization of these two O-methyltransferases showed that the VvOMT3 protein was highly specific and efficient for 2-hydroxy-3-isobutylpyrazine methylation. Based on its differential expression in high- and low-MP-producing grapevine varieties, we propose that VvOMT3 is a key gene for IBMP biosynthesis in grapevine.

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Study of the biosynthesis of 3-isopropyl-2-methoxypyrazine produced by Pseudomonas taetrolens

Cited by 46 publications

References 5 publications

The Biosynthesis of Branched Dialkylpyrazines in Myxobacteria

The Biosynthesis of Branched Dialkylpyrazines in Myxobacteria

Pyrazine Biosynthesis in Corynebacterium glutamicum

Genetic Analysis of the Biosynthesis of 2-Methoxy-3-Isobutylpyrazine, a Major Grape-Derived Aroma Compound Impacting Wine Quality

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