Insights into the molecular interaction between sucrose and alpha-chymotrypsin

One of the most important purposes of enzyme engineering is to increase the thermal and kinetic stability of enzymes, which is an important factor for using enzymes in industry. The purpose of the present study is to achieve a higher thermal stability of alpha-chymotrypsin (alpha-Chy) by modification of the solvent environment. The influence of sucrose was investigated using thermal denaturation analysis, fluorescence spectroscopy, circular dichroism, molecular docking and molecular dynamics (MD) simulations. The results point to the effect of sucrose in enhancing the alpha-Chy stability. Fluorescence spectroscopy revealed one binding site that is dominated by static quenching. Molecular docking and MD simulation results indicate that hydrogen bonding and van der Waals forces play a major role in stabilizing the complex. T-m of this complex was enhanced due to the higher H-bond formation and the lower surface hydrophobicity after sucrose modification. The results show the ability of sucrose in protecting the native structural conformation of alpha-Chy. Sucrose was preferentially excluded from the surface of alpha-Chy which is explained by the higher tendency of water toward favorable interactions with the functional groups of alpha-Chy than with sucrose. (C) 2018 Elsevier B.V. All rights reserved.