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

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.

Interaction of a Short Peptide with G-Quadruplex-Forming Sequences: An SRCD and CD Study

“…Photo-denaturation experiments as well as thermal denaturation experiments [ 45 , 46 , 47 ] were carried out to evaluate the folding stability of the G-quadruplex sequences in the presence and absence of the Rhau25 peptide.…”

Haze Formation and the Challenges for Peptidases in Wine Protein Fining

“…In the presence of polyphenolic compounds, HUPs with lower proline content showed a lower or complete absence of turbidity in model systems, which might result from less proline–phenolic-binding sites . Such phenolic-binding sites have already been reported in a cleft located between the domains I and II of certain TLPs. , Other protein secondary structure elements such as loops in the TLPs can unfold upon heating and become prominent on the protein surface, exposing binding sites for phenolic compounds. , …”

“…22 Such phenolic-binding sites have already been reported in a cleft located between the domains I and II of certain TLPs. 12,23 Other protein secondary structure elements such as loops in the TLPs can unfold upon heating and become prominent on the protein surface, exposing binding sites for phenolic compounds. 3,24 The physicochemical wine environment plays an important role for the induction of protein aggregation.…”

Insights into interactions between food polyphenols and proteins: An updated overview

“…As well as flavonoids and phenolic acids, the studies of tannin‐protein interactions exhibit great similarity in terms of determination methods, health effects, and interaction mechanism. Multi‐spectral analysis and molecular simulation are performed to evaluate the tannin‐protein combination (Di Gaspero et al, 2020), which is attributed to non‐covalent interactions such as hydrogen bonding and hydrophobic interactions in most instances. Besides, tannins exhibit inhibitory effect and disease prevention resemble flavonoids or phenolic acids.…”