Making bovine trypsin more stable and active by Erythritol: A multispectroscopic analysis, docking and computational simulation methods

Abstract

The present study was conducted to investigate the interaction between erythritol as a ligand and bovine trypsin. The interaction of trypsin with ligand was investigated by UV–vis, fluorescence quenching, circular dichroism (CD), activity, molecular docking, and molecular simulation methods. Intrinsic fluorescence intensity of trypsin was slowly quenched by erythritol. The binding constants were taken from the fluorescence quenching analysis. The results displayed the static mode of quenching in the interaction of trypsin with erythritol. Binding constant Ka ≈ 5.72 reflected the relatively moderate affinity of erythritol for trypsin. The negative ΔG° value represented the spontaneous process of the trypsin-erythritol interaction. According to the thermodynamic analysis, effective forces in the formation of the trypsin-erythritol complex were van der Waals interactions and hydrogen bonds. Activity assay also showed that erythritol acted as an activator for trypsin. Far-UV circular dichroism also revealed that erythritol could change the trypsin secondary structure via a slight increase in the α-helix content (from 5.04 to 6.69) and a slight decrease in the β-sheet content (from 40.8 to 38.0). Furthermore, molecular docking and simulation results confirmed the fluorescence results. Generally, erythritol could serve as a stabilizer and an activator for trypsin.