The Secondary Structure of a Major Wine Protein is Modified upon Interaction with Polyphenols.

Mattia Di Gaspero,Giuliano Siligardi,Rohanah Hussain,Andrea Curioni,Paolo Ruzza,Barbara Biondi,Claudia Honisch,Simone Vincenzi,Matteo Marangon

doi:10.3390/molecules25071646

Mattia Di Gaspero, Giuliano Siligardi + Show 7 more

Open Access

https://doi.org/10.3390/molecules25071646

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Abstract

Polyphenols are an important constituent of wines and they are largely studied due to their antioxidant properties and for their effects on wine quality and stability, which is also related to their capacity to bind to proteins. The effects of some selected polyphenols, including procyanidins B1 and B2, tannic acid, quercetin, and rutin, as well as those of a total white wine procyanidin extract on the conformational properties of the major wine protein VVTL1 (Vitis vinifera Thaumatin-Like-1) were investigated by Synchrotron Radiation Circular Dichroism (SRCD). Results showed that VVTL1 interacts with polyphenols as demonstrated by the changes in the secondary (far-UV) and tertiary (near-UV) structures, which were differently affected by different polyphenols. Additionally, polyphenols modified the two melting temperatures (TM) that were found for VVTL1 (32.2 °C and 53.9 °C for the protein alone). The circular dichroism (CD) spectra in the near-UV region revealed an involvement of the aromatic side-chains of the protein in the interaction with phenolics. The data demonstrate the existence of an interaction between polyphenols and VVTL1, which results in modification of its thermal and UV denaturation pattern. This information can be useful in understanding the behavior of wine proteins in presence of polyphenols, thus giving new insights on the phenomena that are involved in wine stability.

Highlights

Polyphenols are important secondary metabolites of higher plants that are extensively studied for their antioxidant properties and related health benefits [1]
This study investigates the interactions between some wine polyphenols, including those above mentioned, and the main wine protein VVTL1 by Synchrotron Radiation Circular Dichroism (SRCD), in order to increase the knowledge on how polyphenols interact with wine proteins
Despite Circular Dichroism being commonly used to study protein binding to ligands [60], this technique was never applied for the study of the interactions of wine proteins with polyphenols, even if this has great relevance for its effects on wine quality

Summary

Introduction

Polyphenols are important secondary metabolites of higher plants that are extensively studied for their antioxidant properties and related health benefits [1]. Polyphenols are generally present in skins and seeds, from where they are extracted at different extents during winemaking, significantly contributing to the physical-chemical and organoleptic properties of resulting wines [2,3]. In addition to their role in determining wine color, the capability of polyphenols to bind to proteins greatly affects. The binding of polyphenols to the (e.g., flavan-3-ol derivatives condensed tannins), improving its organoleptic and stability grape-derived proteins that the arebinding present of in polyphenols wines has been demonstrated [9,10], eventhat if the of properties. Molecules 2020, 25, x agents [6], an operation that consists in adding (e.g.,proteinaceous gelatin, casein, albumin) tooperation a wine to wine astringency [4,5], and it is exploited for wineproteins fining with agents [6], an remove phenolic molecules (e.g., flavan-3-ol derivatives and to condensed improving its that consists in adding proteins (e.g., gelatin, casein, albumin)

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