植物多酚与鲢鱼肌球蛋白相互作用及其对肌原纤维蛋白结构和凝胶形成的影响

The Interaction of Plant Polyphenols with Silver Carp Myosin and Its Effects on the Structure and Gel Formation of Myofibrillar Protein

利用蛋白质同源建模和分子对接技术研究3种常见植物多酚【表没食子儿茶素没食子酸酯(EGCG)、山奈酚、槲皮素】与鲢鱼肌球蛋白的相互作用及位点,并探究EGCG与肌球蛋白结合对整个肌原纤维蛋白结构及聚集行为的影响。采用微波高温加热方式制备蛋白凝胶,研究添加EGCG对鲢鱼肌原纤维蛋白凝胶形成的影响。结果表明:EGCG、山奈酚、槲皮素与肌球蛋白均存在较强的结合,其中EGCG的结合能力最为显著(对接能量最低),且结合方式是氢键、疏水相互作用等非共价作用。这种相互作用改变了整个肌原纤维蛋白的二级结构,即降低了α-螺旋含量,增加了β-转角和无规则卷曲含量,使蛋白质结构松散,这可能有利于后续高温诱导蛋白凝胶的形成。对比分析2种加热方式(水浴和微波)诱导蛋白凝胶形成的差异,发现与水浴加热相比,微波加热能显著提高肌原纤维蛋白的破断强度、凹陷深度及凝胶强度。在微波加热制备蛋白凝胶的基础上,添加0.125~1 mg/mL EGCG均能改善肌原纤维蛋白的凝胶特性,且改善作用在添加量为0.5 mg/mL时达到最大,此时其凹陷深度和凝胶强度分别增加了59.9%和89.8%。结论:添加EGCG并微波加热可改善鲢鱼肌原纤维蛋白的凝胶特性,其机理可能是:EGCG与肌球蛋白相互作用,改变了整个肌原纤维蛋白的结构和聚集行为。本研究结果为提高淡水鱼糜制品的品质提供试验依据。

This study aimed to investigate the molecular interactions of silver carp myosin and three common plant polyphenols(EGCG,kaempferol,and quercetin)by protein homology modeling and molecular docking techniques.Moreover,the effects of EGCG binding to the myosin on entire structure of myofibrillar protein and its aggregation behavior were further explored,and the effect of tea polyphenol supplementation on microwave heating-induced gel formation of myofibrillar protein from silver carp was finally determined.The results showed that EGCG,kaempferol,and quercetin had the strong capacities to bind with myosin.Among them,EGCG had the greatest binding ability with the lowest docking energy,and the main interaction was noncovalent interaction including hydrogen bond and hydrophobic interaction.This interaction altered the secondary structure of myofibrillar protein,which reducedα-helix content,but increasedβ-turn and random coil contents,leading to a more unfolded structure of protein and its potential gel formation induced by high temperature.Furthermore,microwave heating contributed to the improved gel properties of myofibrillar protein as compared with water bath heating.Indeed,addition of 0.125-1 mg/mL EGCG could further improve the properties of microwave heating-induced myofibrillar protein gel.The beneficial effects of EGCG reached the maximum when the addition amount was 0.5 mg/mL,and the deformation and gel strength were increased by 59.9%and 89.8%,respectively.Therefore,the addition of EGCG and microwave heating could improve the gel properties of myofibrillar protein from sliver carp,and its mechanism was possible to be structure alteration and aggregation behavior of myofibrillar protein stimulated by interaction of EGCG with myosin.Our results may provide experimental and theoretical basis for improving the quality of surimi products of freshwater fish.