去折叠态β-乳球蛋白与表没食子儿茶素没食子酸酯的相互作用

Interaction between Unfolded Bovine β-Lactoglobulin and Epigallocatechin Gallate

通过微波处理β-乳球蛋白(β-lactoglobulin,β-LG)得到去折叠态β-乳球蛋白(unfolded-β-lactoglobulin,U-β-LG),采用荧光光谱、紫外-可见光谱、圆二色光谱的方法研究表没食子儿茶素没食子酸酯(epigallocatechingallate,EGCG)与U-β-LG的相互作用机制。结果表明,EGCG能与β-LG和U-β-LG相互作用形成复合物。它们相互之间均主要为疏水作用力。在298 K时,EGCG与β-LG和U-β-LG的结合距离分别为3.188 nm和2.875 nm。EGCG的结合使β-LG和U-β-LG的二、三级结构发生变化,表面疏水性降低。与天然β-LG相比,U-β-LG与EGCG具有更大的结合强度,结合后的U-β-LG发生更大的结构变化。

The interaction mechanism of unfolded bovineβ-lactoglobulin(U-β-LG)with epigallocatechin gallate(EGCG)was investigated by using fluorescence,ultraviolet and circular dichroism(CD)spectroscopy.U-β-LG was obtained afterβ-lactoglobulin(β-LG)was treated by microwave.It was shown that EGCG could interact withβ-LG or U-β-LG to formβ-LG-EGCG complex or U-β-LG-EGCG complex.The main binding force between EGCG andβ-LG or U-β-LG was hydrophobic interaction.The binding distance between donor and acceptor at 298 K were 3.188 and 2.875 nm forβ-LG-EGCG complex and U-β-LG-EGCG complex,respectively based on the F?rster's theory of non-radiative energy transfer.The two-and three-dimensional structures ofβ-LG and U-β-LG were changed and their surface hydrophobicity was decreased slightly after being combined with EGCG.The binding affinity between U-β-LG and EGCG was stronger than that betweenβ-LG and EGCG,which contributed to greater conformational change of U-β-LG.