Exploration of Binding Interaction of β-1,3-D-Glucan and Patulin by Molecular Dynamics Simulation Study

Patulin (PAT) contaminant in apple juice has attracted extensive attention. As a biosorbent, beta-1, 3-D-glucan shows great advantages in removing toxic contaminants. The aim of this study was to reveal the adsorption mechanisms of PAT by beta-1, 3-D-glucan. Four beta-1, 3-D-glucans with different number of side chains: curdlan, a hypothetical glucan, schizophyllan (SPG) and lentinan were simulated. Performance of molecular docking was observed to predict the binding mode and affinity. The most potential compounds were performed molecular dynamics (MD) simulation. The results show that the interaction between beta-1, 3-D-glucan and PAT is driven by steric complementarity, intermolecular H-bond and Pi-Sigma interaction. SPG has a large internal helical space to facilitate the insertion of PAT into the helix, and has relatively strong interaction with PAT. The side and main chains form a cavity to wrap PAT inside the helix. Furthermore, the binding free energy calculation was carried out using Molecular Mechanics-Generalized Born Surface Area (MM-GBSA) approach. SPG showed high negative Delta G(bind) value. Structural and energetic analyses demonstrated the adsorption characteristics of the four beta-1, 3-D-glucans. SPG is the most promising adsorbent for PAT. The side chain plays a major role in the adsorption process of the beta-1, 3-D-glucans. It provides a basis for the development of beta-1, 3-D-glucan as PAT adsorbent.