Binding Sites of Resveratrol, Genistein, and Curcumin with Milk α- and β-Caseins

Abstract

The binding sites of antioxidant polyphenols resveratrol, genistein, and curcumin are located with milk α- and β-caseins in aqueous solution. FTIR, CD, and fluorescence spectroscopic methods and molecular modeling were used to analyze polyphenol binding sites, the binding constant, and the effects of complexation on casein stability and conformation. Structural analysis showed that polyphenols bind casein via hydrophilic and hydrophobic interactions with the number of bound polyphenol molecules (n) 1.20 for resveratrol, 1.42 for genistein, and 1.43 for curcumin with α-casein and 1.14 for resveratrol, 1.27 for genistein, and 1.27 for curcumin with β-casein. The overall binding constants of the complexes formed are K(res-α-casein) = 1.9 (±0.6) × 10(4) M(-1), K(gen-α-casein) = 1.8 (±0.4) × 10(4) M(-1), and K(cur-α-casein) = 2.8 (±0.8) × 10(4) M(-1) with α-casein and K(res-β-casein) = 2.3 (±0.3) × 10(4) M(-1), K(gen-β-casein) = 3.0 (±0.5) × 10(4) M(-1), and K(cur-β-casein) = 3.1 (±0.5) × 10(4) M(-1) for β-casein. Molecular modeling showed the participation of several amino acids in polyphenol-protein complexes, which were stabilized by the hydrogen bonding network with the free binding energy of -11.56 (resveratrol-α-casein), -12.35 (resveratrol-β-casein), -9.68 (genistein-α-casein), -9.97 (genistein-β-casein), -8.89 (curcumin-α-casein), and -10.70 kcal/mol (curcumin-β-casein). The binding sites of polyphenols are different with α- and β-caseins. Polyphenol binding altered casein conformation with reduction of α-helix, indicating a partial protein destabilization. Caseins might act as carriers to transport polyphenol in vitro.

Synthesis and Biophysical Insights into the Binding of a Potent Anti-Proliferative Non-symmetric Bis-isatin Derivative with Bovine Serum Albumin: Spectroscopic and Molecular Docking Approaches

“…However, in the present study, for such a compound in the early stages of development, BSA was employed as a model representing the serum albumins family. Several earlier studies have utilized spectroscopic techniques, particularly fluorescence spectral determination, to explore the different aspects of protein binding to various ligands [34][35][36]. Fluorescence quenching shows decline protein intrinsic fluorescence occurring through diverse molecular interactions [37,38].…”

Antioxidant activity and bioaccessibility of phenols-enriched edible casein/caseinate coatings during in vitro digestion

“…According to Dufour & Dangles (2005), the binding constant was calculated using intensity at 340 nm (tryptophan emission wavelength). In addition, binding parameters were determined using the Stern-Volmer equation (Lakowicz, 2006;Bourassa et al 2013). Non-linear regression analysis was performed to calculate KD (dissociation constant) and n (number of binding site).…”

Study of the Interactions Occurring During the Encapsulation of Sesamol within Casein Micelles Reformed from Sodium Caseinate Solutions

“…In contrast, Bourassa et al. () observed an bathochromic shift for the interaction between resveratrol and α‐ and β‐caseins, which indicated a different interaction when compared with genistein and curcumin with the same caseins. Recently, He, Xu, Zeng, Qin, and Chen () reported a similar bathochromic shift for the interaction between malvin‐3‐ O ‐glucoside and α and β caseins, suggesting a change in the microenvironment into a more polar one.…”