基于分子对接技术研究鱼源抗冻多肽与鱼肌球蛋白的相互作用

Prediction of Interaction between Fish-derived Antifreeze Peptides and Fish Myosin by Molecular Docking

冻藏期间蛋白质冷冻变性是引起解冻后鱼糜凝胶化能力下降的主要原因之一,而肌球蛋白重链(Myosin Heavy Chain,MHC)是鱼糜凝胶形成的主要贡献者。本研究使用不同生物酶酶解制备抗冻多肽,通过计算机模拟酶解技术筛选抗冻多肽。利用蛋白质同源建模构建海鲈鱼肌球蛋白空间结构,通过分子对接和分子动力学模拟解析抗冻多肽与海鲈鱼肌球蛋白重链的作用位点及可能的作用机制。结果表明,胰蛋白酶酶解物具有高抗冻活性,对菌体低温胁迫保护达到80.35%±4.39%,并具有良好的热滞活性及抑制重结晶作用。模拟胰蛋白酶酶解获得的肽段GPR与GPAGGK可以与肌球蛋白重链通过分子间作用力结合,其中GPAGGK的结合更为稳定。这种相互作用可以阻碍肌球蛋白在温度变化中的结构改变,其机理可能是抗冻多肽结合在肌球蛋白重链的结构空腔上,影响了结合水解离后引起的疏水键及二硫键等化学键的形成,阻碍蛋白侧链聚集、结构改变和冰晶的位移等,这有利于鱼糜及鱼糜制品在冷冻贮藏中的品质保持。本研究结果为抗冻多肽应用于鱼糜及其制品在冷冻贮藏过程中品质保持的应用提供科学依据。

Freeze denaturation during frozen storage is one of the main reasons for the decreased gelation ability of surimi after thawing.The myosin heavy chain(MHC)is the major contributor to the formation of surimi gel.In this study,the antifreeze peptides were prepared by hydrolysis of different enzymes and screened by computer simulated enzymatic hydrolysis technology.The spatial structure of sea bass myosin was constructed by protein homology modeling.The action sites and possible mechanism of sea bass myosin heavy chain with antifreeze peptides were analyzed by molecular docking and molecular dynamics simulation techniques.The results showed that the trypsin hydrolysates possessed high antifreeze activity,which the survival rate of bacteria was 80.35%±4.39% after freeze-thaw cycle,and had thermal hysteresis and ice recrystallization inhibition activity.The peptides GPR and GPAGGK obtained by simulated trypsin enzymolysis could combine with the myosin heavy chain by intermolecular force,and the binding of peptide GPAGGK to myosin was more stable.This binding could block the myosin structural changes in response to temperature change.The mechanism might be that the antifreeze peptides combine with the structural cavity of the myosin heavy chain,which affected the formation of hydrophobic bonds and disulfide bonds caused by the dissociation of the bound water.Thus the aggregation of protein side chains,structural changes and ice crystal displacement were impeded,which was conducive to the quality maintenance of surimi and surimi products in cryopreservation.This study would provide a theoretical basis for the application of antifreeze peptides in the quality maintenance of surimi and its products during frozen storage.