铁蛋白与绿原酸的非共价相互作用

Non-covalent Interactions between Ferritin and Chlorogenic Acid

该研究探讨了绿原酸与植物源铁蛋白的相互作用,结合荧光光谱、圆二色谱、透射电子显微镜、动态光散射等对二者相互作用机制进行了表征和分析。结果显示,绿原酸能与重组大豆种子铁蛋白(rH-2)发生相互作用,引起铁蛋白三级/四级结构的变化,而对其一级/二级结构无影响。荧光结果表明绿原酸并没有改变铁蛋白的特征发射峰330 nm,且随着浓度的升高,铁蛋白荧光强度下降,在这种非共价结合中氢键/范德华力起主要作用。在25、37、55℃下,二者的结合常数K分别为1.7×10^(4)(mol/L)^(-1),1.4×10^(4)(mol/L)^(-1)和1.04×10^(4)(mol/L)^(-1),结合位点数n分别为156.8、132.1和93.9,表明随温度的升高,绿原酸与铁蛋白的相互作用强度呈下降趋势。动态光散射结果显示加入绿原酸前后粒径分别为7.61 nm和7.67 nm,未发生显著变化,表明绿原酸不能诱导铁蛋白之间的聚合。铁蛋白-绿原酸复合物(FCAs)中绿原酸的抗氧化能力得以保留但略有下降。研究结果进一步提高了对不同食物组分尤其是铁蛋白和酚酸相互作用机制的理解。

The mechanisms by which chlorogenic acid(CA;a phenolic compound)and ferritin[from the recombinant soybean seed H-2(rH-2)]interact with each other were examined using fluorescence spectroscopy,circular dichroism spectroscopy,transmission electron microscopy,and dynamic light scattering.The results showed that CA could interact with phytoferritin,causing changes in the tertiary/quaternary structure of the iron-storing protein but not in its primary/secondary structure.The phenolic compound did not change the characteristic emission peak of ferritin at 330 nm,the fluorescence intensity of which decreased with increasing CA concentrations.Hydrogen bonds/van der Waals forces played a major role in the non-covalent interactions between CA and ferritin,the binding constants(K)for which were 1.7×10^(4),1.4×10^(4),and 1.04×10^(4)(mol/L)^(-1),with 156.8,132.1,and 93.9 binding sites(n),at 25,37,and 55℃,respectively.These results indicate that the strength of the interaction between CA and ferritin decreases with increasing temperature.According to the dynamic light scattering results,the particle size of ferritin did not change significantly before(7.61)and after(7.67)the addition of CA,indicating that the phenolic compound does not induce the aggregation of ferritin molecules.Additionally,the antioxidative capacity of CA in the ferritin-CA complexes was preserved,albeit slightly decreased.These results further enhance understanding of the interactions between different food components,especially ferritin and phenolic acids.