College of Food Science, Shenyang Agriculture University, Shenyang 110866, China.
College of Food Science, Shenyang Agriculture University, Shenyang 110866, China.
Food Chem. 2020 Oct 1;326:126804. doi: 10.1016/j.foodchem.2020.126804. Epub 2020 Apr 13.
This study aimed to examine the interaction mechanism between xylitol (XY) and whey protein isolate (WPI) using multispectral techniques and molecular docking. Additionally, we investigated the effect of XY on WPI functionality using the method of fluorescent probe, high-speed dispersion and differential scanning calorimetry. The fluorescence quenching results such as quenching constants, binding constants and thermodynamic parameters showed strong susceptibility to interacting of WPI and its fractions to XY and the sequence was: α-lactalbumin (α-La) > bovine serum albumin (BSA) > β-lactoglobulin (β-Lg). Docking results revealed that XY was bound to the residues of aromatic cluster II in α-La, the hydrophobic cavity of β-Lg and the subdomain IIA of BSA through hydrogen bonding and van der Waals forces, resulting in conformational changes in secondary structures of proteins, which converted α-helix to β-turn and random coils. Further, XY increased thermal stability and emulsifying properties and reduced surface hydrophobicity and zeta-potential of WPI.
本研究旨在使用多光谱技术和分子对接研究木糖醇（XY）和乳清蛋白分离物（WPI）之间的相互作用机制。此外，我们还使用荧光探针法、高速分散法和差示扫描量热法研究了 XY 对 WPI 功能的影响。荧光猝灭结果，如猝灭常数、结合常数和热力学参数表明，WPI 及其各部分与 XY 的相互作用具有很强的敏感性，其顺序为：α-乳白蛋白（α-La）>牛血清白蛋白（BSA）>β-乳球蛋白（β-Lg）。对接结果表明，XY 通过氢键和范德华力与α-La 的芳香簇 II 残基、β-Lg 的疏水性腔和 BSA 的亚结构域 IIA 结合，导致蛋白质二级结构发生构象变化，将α-螺旋转化为β-转角和无规卷曲。此外，XY 提高了 WPI 的热稳定性和乳化性能，降低了 WPI 的表面疏水性和 zeta 电位。
