表没食子儿茶素没食子酸酯通过结合稳定去载脂蛋白 α-乳白蛋白：实验和分子动力学研究。
Stabilization of apo α-lactalbumin by binding of epigallocatechin-3-gallate: Experimental and molecular dynamics study.
机构信息
Center for Chemistry - Institute of Chemistry, Technology and Metallurgy, University of Belgrade, Belgrade, Serbia.
Center of Excellence for Molecular Food Sciences & Department of Biochemistry, University of Belgrade - Faculty of Chemistry, Belgrade, Serbia.
出版信息
Food Chem. 2019 Apr 25;278:388-395. doi: 10.1016/j.foodchem.2018.11.038. Epub 2018 Nov 13.
α-Lactalbumin (ALA) is a Ca-binding protein which constitutes up to 20% of whey protein. At acidic pH, and in the apo-state at elevated temperatures, ALA is the classic 'molten globule' (MG). This study examined epigallocatechin-3-gallate (EGCG) binding to ALA in its apo form (apoALA) and stabilizing effect on protein structure thereof. EGCG binds to apoALA in both native and MG state. The complex of EGCG and ALA is more stable to thermal denaturation. The docking analysis and molecular dynamic simulation (MDS) showed that Ca removal decreased conformational stability of ALA, because of the local destabilization of Ca-binding region. EGCG binding to apoALA increases its stability by reverting of conformation and stability of Ca-binding region. Therefore, EGCG-induced thermal stability of apoALA is based on increased apoALA conformational rigidity. This study implies that during gastric digestion of tea with milk EGCG would remain bound to ALA, albeit in the Ca-free form.
α-乳白蛋白（ALA）是一种 Ca 结合蛋白，占乳清蛋白的 20%。在酸性 pH 值和高温下的无 Ca 状态下，ALA 是典型的“熔融球蛋白”（MG）。本研究考察了表没食子儿茶素没食子酸酯（EGCG）与无 Ca 形式的 ALA（apoALA）的结合及其对蛋白质结构的稳定作用。EGCG 在天然和 MG 状态下均可与 apoALA 结合。与热变性相比，EGCG 和 ALA 的复合物更稳定。对接分析和分子动力学模拟（MDS）表明，由于 Ca 结合区域的局部失稳，Ca 去除会降低 ALA 的构象稳定性。EGCG 通过构象的恢复和 Ca 结合区域的稳定性增加来增加 apoALA 的稳定性。因此，EGCG 诱导 apoALA 的热稳定性基于 apoALA 构象刚性的增加。本研究表明，在茶与牛奶一起进行胃消化时，EGCG 虽然以无 Ca 形式存在，但仍与 ALA 结合。
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