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Please use this identifier to cite or link to this item: http://dspace.utalca.cl/handle/1950/8808

Title: Biosynthesis of Methoxypyrazines: Elucidating the Structural/Functional Relationship of Two Vitis vinifera O-Methyltransferases Capable of Catalyzing the Putative Final Step of the Biosynthesis of 3-Alkyl-2-Methoxypyrazine
Authors: Vallarino, J.G.
Lopez-Cortes, X.A.
Dunlevy, J.D.
Boss, P.K.
Gonzalez-Nilo, F.D.
Moreno, Y.M.
Keywords: methoxypyrazines
methyltransferases
Vitis vinifera
wine
flavor
docking simulation
QM/MM
Issue Date: Jul-2011
Publisher: AMER CHEMICAL SOC
Citation: JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY Volume: 59 Issue: 13 Pages: 7310-7316 DOI: 10.1021/jf200542w Published: JUL 13 2011
Abstract: 3-Alkyl-2-methoxypyrazines (MPs) are an important food constituent and have been associated with detrimental herbaceous flavors in red wines by consumers and the wine industry. The Vitis vinifera genes O-methyltransferase 1 and 2 (VvOMT1 and VvOMT2) have been isolated in the grapevine cultivar Carmenere. These genes encode S-adenosyl-L-methionine (SAM)-dependent O-methyltransferases, which have the ability to methylate 3-alkyl-2-hydroxypyrazines (HPs)-the putative final step in MPs production. Atomic studies were performed in order to explain the differences in these VvOMT activities through their structural/functional relationship in MPs biosynthesis. Differences in enthalpy energy observed between the proteins maybe due to changes of equivalent residues in the active sites of VvOMT1 (F319, L322) and VvOMT2 (L319, V322). However, docking simulations and QM/MM analyses described how residues H272 and M182 could explain the main functional differentiation observed between VvOMT1 and VvOMT2 through steric impediment, which limits the formation of the transition state in enzymes encoded by VvOMT2. Therefore, this finding could explain the decreasing catalytic efficiency observed for VvOMT2.
Description: Moreno, YM (reprint author), Univ Talca, Fac Ciencias Agr, Ctr Tecnol Vid & Vino, Talca, Chile.
URI: http://dspace.utalca.cl/handle/1950/8808
ISSN: 0021-8561
Appears in Collections:Artículos en publicaciones ISI - Universidad de Talca

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