Mechanisms of persimmon pectin methyl esterase activation by high pressure processing based on chemical experiments and molecular dynamics simulations

Abstract

High pressure processing (HPP) was found to have a kinase effect on persimmon pectin methyl esterase (PME), while the mechanism remains unclear. In this study, chemical experiments and molecular dynamics (MD) simulations were used to reveal its mechanisms. Persimmon PME was first extracted and purified using ion exchange columns with 81.89% purity. After 500 MPa/5 min, PME activity increased 11.3%, the α-helix and β-folding decreased 10.8% and 6.1% compared to the 0.1 MPa group, respectively. MD results showed that HPP decreased the volume, increased the number of hydrogen bonds between PME and pectin. Under high pressure, Asp-157, Asp-136 and Gln-135 in the enzyme activity center remained stable, while the positions of Arg-225 and Gln-113 changed a lot. The conformation of the substrate binding channel also changed. The secondary structure and volume changes of the HPP-treated PME affected the active center and substrate channels, ultimately altering the activity.