Binding parameters and molecular dynamics of β-lactoglobulin-vanillic acid complexation as a function of pH - Part A: Acidic pH
Binding parameters and molecular dynamics of β-lactoglobulin-vanillic acid complexation as a function of pH - Part A: Acidic pH
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DOI：
10.1016/j.foodchem.2021.130059
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发表时间：
2021-05-21
期刊：
影响因子：
8.8
通讯作者：
Kasapis, Stefan
中科院分区：
文献类型：
--
作者：
Abdollahi, Kourosh;Condict, Lloyd;Kasapis, Stefan
通常使用不适当的线性方程来研究蛋白质-酚类化合物的相互作用，以分析结合强度和化学计量。这项工作利用更合适的方案来研究 pH 2.4 下香草酸和 β-乳球蛋白之间的分子相互作用，其中蛋白质主要作为单体存在。对荧光数据进行非线性结合和工作图分析，有效确定相互作用的解离常数（K-D，2.93 x 10^-5）M）和化学计量（1：1）。此外，光谱技术揭示了络合后β-乳球蛋白的构象特征发生了统计学上显着的变化。分子动力学 (MD) 模拟支持 1:1 相互作用化学计量，并揭示香草酸的稳定本质上是动态的，但主要由位于单体 β 桶内的四个 π-烷基相互作用和一个氢键支持。 MD模拟分析中通常不考虑水分子，但水分子被证明是通过桥联相互作用稳定配体的重要因素。
Protein-phenolic compound interactions are commonly investigated with inappropriate linear equations for the analysis of binding strength and stoichiometry. This work utilises more appropriate protocols for the investigation of molecular interactions between vanillic acid and beta-lactoglobulin at pH 2.4, where the protein predominately exists as a monomer. Non-linear binding and Job plot analysis were conducted on fluorescence data to effectively determine the interaction's dissociation constant (K-D, 2.93 x 10(-5) M) and stoichiometry (1:1). Furthermore, spectroscopic techniques revealed statistically significant alterations to the conformational characteristics of beta-lactoglobulin upon complexation. Molecular dynamics (MD) simulations support a 1:1 interaction stoichiometry and reveal that the stabilisation of vanillic acid was dynamic in nature but mainly supported by four pi-alkyl interactions and one hydrogen bond, located within the beta-barrel of the monomer. Water molecules, which are generally not accounted for in MD simulation analysis, were shown to be an important factor in the ligand stabilization via bridging interactions.