β-glucosidase from Hevea brasiliensis seeds: Purification, homology modeling, and insights into the substrate-binding model.

The isolation of β-glucosidase from Hevea brasiliensis (Hbglu) seeds was investigated and a homology model was built on the MODELLER software to understand the structure feature. The quality of the model was evaluated on PROCHEK. The refined model was used for molecular docking on AutoDock 4.2 to determine the substrate- binding sites and potential substrates based on their calculated binding affinities. The substrate specificity of Hbglu was verified through the kinetic measurement of hydrolytic activities. Molecular dynamic simulations of cyanogenic β-glucosidase and ligand-bound complex showed that the free energy (ΔG) for the binding of p-nitrophenyl-β-D-glucopyranoside and daidzein-7-O-β-D-glucoside were -8.6 and -7.92 kcal/mol, respectively. Thus, daidzein-7-O-β-D-glucoside is a potential substrate. Future studies on the physicochemical properties and catalytic mechanisms will provide information on the molecular biological properties of Hbglu. PRACTICAL APPLICATIONS: This study reported the 3D structural simulation of β-glucosidase from Hbglu. The docking condition between Hbglu and various different substrates were assessed on Autodock. The results can be used as reference in designing enzymes, and improving the utilization of β-glucosidases for the hydrolysis of flavor precursors from fruits, teas, and wines and for the production of flavonoid compounds and cyanogenic glycoside degradation.