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

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.