College of Food Science, Shenyang Agriculture University, Shenyang, 110866, China.
College of Food Science, Shenyang Agriculture University, Shenyang, 110866, China.
Colloids Surf B Biointerfaces. 2021 Oct;206:111930. doi: 10.1016/j.colsurfb.2021.111930. Epub 2021 Jun 17.
The molecular interactions of xylitol (XY) with α-casein (α-CN) and κ-casein (κ-CN) at pH 7.4 as a function of temperature (298, 308, and 318 K) were characterized by multispectral techniques and molecular docking. The fluorescence results showed that XY strongly quenched the intrinsic fluorescence of α- and κ-CN by static quenching, as well as the presence of a single binding site for XY on both proteins with a binding constant value of ∼10 L/mol. The binding affinity of both proteins for XY decreased with increasing temperature, and Van der Waals forces, hydrogen bonding and protonation were the key forces in the interactions. The addition of XY altered the polarity of the microenvironment of proteins and changed their secondary structure from ordered to disordered. The molecular docking results showed that XY had different binding sites to α- and κ-CN, with several amino acids involved in the binding processes.
木糖（XY）与α-酪蛋白（α-CN）和κ-酪蛋白（κ-CN）在 pH 7.4 下的分子相互作用作为温度的函数（298、308 和 318 K）通过多光谱技术和分子对接进行了表征。荧光结果表明，XY 通过静态猝灭强烈猝灭α-和κ-CN 的本征荧光，以及在两种蛋白质上存在一个用于 XY 的单一结合位点，结合常数值约为 10 L/mol。两种蛋白质与 XY 的结合亲和力随温度升高而降低，范德华力、氢键和质子化是相互作用的关键力。XY 的添加改变了蛋白质微环境的极性，并使它们的二级结构从有序变为无序。分子对接结果表明，XY 与α-CN 和κ-CN 具有不同的结合位点，涉及几个氨基酸参与结合过程。
