β-乳球蛋白与黑米花色苷的相互作用

Interaction between β-Lactoglobulin and Black Rice Anthocyanin

从荧光光谱、同步荧光光谱、紫外-可见光谱、抗氧化能力和分子对接等方面,研究黑米花色苷(black rice anthocyanin,BRA)与β-乳球蛋白(β-lactoglobulin,β-LG)在模拟生理条件下的相互作用。结果显示,BRA对β-LG具有较强的荧光猝灭,猝灭方式为静态猝灭,说明二者发生相互结合,同时计算了结合位点数和结合常数,热力学参数表明疏水作用力为其主要的作用力;根据非辐射能量转移理论,结合距离r为3.14 nm。同步荧光光谱结果显示,BRA与β-LG的相互作用影响乳球蛋白的构象,但不影响色氨酸和酪氨酸的微环境;分子对接结果显示BRA中的主要成分矢车菊-3-O-葡萄糖苷与β-LG的结合主要是疏水作用力,该结果与热力学参数分析结果相一致。

In this work,we studied the interaction between black rice anthocyanin(BRA)andβ-lactoglobulin(β-LG)by fluorescence spectroscopy,synchronous fluorescence spectroscopy,ultraviolet-visible spectroscopy,antioxidant capacity and molecular docking under simulated physiological conditions.The results showed that black rice anthocyanin had a strong ability to quench the fluorescence ofβ-lactoglobulin in a static mode.The binding constants(Ka)and site numbers(n)were obtained at different temperatures.The major interaction force was hydrophobic interaction in the binding of BRA toβ-lactoglobulin based on the thermodynamic parameters.According to F?rster’s non-radiative energy transfer theory,the donor-acceptor proximity in BRA-β-LG complex was calculated as3.14nm.The synchronous fluorescence spectra revealed that interaction with BRA caused conformational changes inβ-LG,but did not affect the microenvironment of tryptophan and tyrosine residues.Molecular docking indicated that the main driving force of the interaction between cyaniding-3-O-glucoside(the major component of black rice anthocyanin)andβ-lactoglobulin was hydrophobic interaction,which was consistent with the result obtained from thermodynamic parameter analysis.