Applied Molecular Thermodynamics Group (THERMA), Department of Food Technology, Federal University of Viçosa, Av. P. H. Rolfs s/n, Viçosa, MG 36570900, Brazil.
Colloidal and Macromolecular Green Chemistry Group (QUIVECOM), Department of Chemistry, Federal University of Viçosa, Av. P. H. Rolfs s/n, Viçosa, MG 36570900, Brazil.
Food Res Int. 2022 Aug;158:111567. doi: 10.1016/j.foodres.2022.111567. Epub 2022 Jun 25.
Despite some thermodynamics studies about β-lactoglobulin (βLG) and resveratrol (RES) interactions, there is a gap regarding kinetics data about βLG-RES complex formation. Here, we determined the kinetic and thermodynamic parameters of βLG-RES interactions by using surface plasmon resonance (SPR). The kinetic association parameters were dependent on the 3D water structure present on the solvation shell of both interacting molecules. At lower temperature (285.15 K), all activation energies were positive (E= 82.86 kJ.mol,TΔS= 32.26 kJ.mol, and ΔC= 4.15 kJ.molK) due to the higher water structuration on the RES and βLG solvation shell. All these energetic barriers become mainly from the energetic cost for the desolvation process of RES and βLG. At higher temperature (301.15 K), the solvation water structure decreases and all the above activation energies become negative (E=-121.58 kJ.mol,TΔS=-173.59 kJ.mol, and ΔC=-29.92 kJ.molK) because the direct interaction between desolvated RES and βLG molecules released more energy than it is absorbed by desolvation process. However, kinetic dissociation parameters were not dependent on the hydrogen bond density of the water solvation shell as showed by the temperature independence of dissociation energetic parameters. This non-dependence of the dissociation process from the desolvation step probably is because the water molecules interacting with the βLG-RES complex is not concentrated around/inside the protein site of interaction. The association of free molecules was 1.5 times faster than the dissociation of the thermodynamically stable complex (ΔG ≅ 48.15 kJ.mol, ΔG ≅ 73.10 kJ.mol). The lower free energy barrier observed for the association came from an isokinetic process where entropic and enthalpic parameters compensated for each other. The ΔG° values indicate that the thermodynamically stable complex predominates over free molecules. At low temperature (285.15 K), the hydrophobic interaction (ΔH° = 73.06 kJ.mol; TΔS° = 99.60 kJ.mol) drove the βLG-RES complex formation while at high temperature (301.15 K), hydrophilic interactions became dominant (ΔH° = -142.50 kJ.mol; TΔS° = -118.18 kJ.mol).
尽管已经有一些关于β-乳球蛋白（βLG）和白藜芦醇（RES）相互作用的热力学研究，但关于βLG-RES 复合物形成的动力学数据仍存在空白。在这里，我们通过使用表面等离子体共振（SPR）来确定βLG-RES 相互作用的动力学和热力学参数。动力学关联参数取决于相互作用分子溶剂化壳中存在的 3D 水结构。在较低温度（285.15 K）下，由于 RES 和 βLG 溶剂化壳上水结构的更高程度，所有活化能均为正值（E=82.86 kJ/mol，TΔS=32.26 kJ/mol，ΔC=4.15 kJ/molK）。所有这些能量障碍主要来自 RES 和 βLG 的去溶剂化过程的能量成本。在较高温度（301.15 K）下，溶剂化水结构减少，所有上述活化能变为负值（E=-121.58 kJ/mol，TΔS=-173.59 kJ/mol，ΔC=-29.92 kJ/molK），因为去溶剂化的 RES 和 βLG 分子之间的直接相互作用释放的能量超过去溶剂化过程吸收的能量。然而，由于动力学解离参数不受水溶剂化壳氢键密度的影响，因此温度对解离能参数没有影响。这种解离过程与去溶剂化步骤的不依赖性可能是因为与βLG-RES 配合物相互作用的水分子并未集中在蛋白质相互作用部位周围/内部。自由分子的缔合速度比热力学稳定配合物的解离速度快 1.5 倍（ΔG ≅ 48.15 kJ/mol，ΔG ≅ 73.10 kJ/mol）。观察到的较低自由能障碍来自等动力学过程，其中熵和焓参数相互补偿。ΔG°值表明热力学稳定配合物占主导地位。在低温（285.15 K）下，疏水相互作用（ΔH°=73.06 kJ/mol；TΔS°=99.60 kJ/mol）驱动βLG-RES 配合物的形成，而在高温（301.15 K）下，亲水相互作用占主导地位（ΔH°=-142.50 kJ/mol；TΔS°=-118.18 kJ/mol）。
