National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian 116034, PR China.
Int J Biol Macromol. 2021 Jul 1;182:849-857. doi: 10.1016/j.ijbiomac.2021.04.072. Epub 2021 Apr 14.
In this study, the effect of pulsed electric field (PEF) on apparent morphology and molecular structure of shell-like ferritin obtained from horse spleen was determined by circular dichroic (CD), fluorescence spectroscopy, Raman spectroscopy, cold field emission scanning electron microscopy (CF-SEM) and transmission electron microscopy (TEM), and verified by molecule dynamics (MD) simulation. After PEF treatment, the α-helix content of the samples reached a minimum value at 10 kV/cm, which indicated that the ferritin structure has been partially unfolded. However, the α-helix content peaked again after resting for 2 h at 25 ± 1 °C. This indicated that the PEF-treated ferritin tended to restore its original spherical morphology probably owing to the reversible assembly characteristic of ferritin. In addition, microstructure analysis revealed that ferritin particles aggregated after PEF treatment. Therefore, PEF treatment could induce the "exposure" of hydrophobic amino acids and conversion of disulfide bond configuration, and consequently, regulate the internal cavity stability of ferritin. The research will be beneficial to expand the application of PEF treatment in the modification of protein structure, and provide a theoretical basis for the application of ferritin as a carrier of bioactive molecules in food.
本研究采用圆二色性（CD）、荧光光谱、拉曼光谱、冷场发射扫描电子显微镜（CF-SEM）和透射电子显微镜（TEM）等方法，结合分子动力学（MD）模拟，确定脉冲电场（PEF）对马脾铁蛋白壳状结构的表观形态和分子结构的影响。PEF 处理后，样品的α-螺旋含量在 10 kV/cm 时达到最小值，表明铁蛋白结构已部分展开。然而，在 25±1°C 下静置 2 h 后，α-螺旋含量再次达到峰值。这表明，PEF 处理后的铁蛋白可能由于铁蛋白的可逆组装特性而倾向于恢复其原始的球形形态。此外，微观结构分析表明，铁蛋白颗粒在 PEF 处理后聚集。因此，PEF 处理可以诱导疏水性氨基酸的“暴露”和二硫键构象的转换，从而调节铁蛋白内部腔稳定性。该研究将有助于拓展 PEF 处理在蛋白质结构修饰中的应用，并为铁蛋白作为食品中生物活性分子载体的应用提供理论依据。
