A Possible Mechanism of Graphene Oxide to Enhance Thermostability of D-Psicose 3-Epimerase Revealed by Molecular Dynamics Simulations

Abstract

Thermal stability is a limiting factor for effective application of D-psicose 3-epimerase (DPEase) enzyme. Recently, it was reported that the thermal stability of DPEase was improved by immobilizing enzymes on graphene oxide (GO) nanoparticles. However, the detailed mechanism is not known. In this study, we investigated interaction details between GO and DPEase by performing molecular dynamics (MD) simulations. The results indicated that the domain (K248 to D268) of DPEase was an important anchor for immobilizing DPEase on GO surface. Moreover, the strong interactions between DPEase and GO can prevent loop α1′-α1 and β4-α4 of DPEase from the drastic fluctuation. Since these two loops contained active site residues, the geometry of the active pocket of the enzyme remained stable at high temperature after the DPEase was immobilized by GO, which facilitated efficient catalytic activity of the enzyme. Our research provided a detailed mechanism for the interaction between GO and DPEase at the nano–biology interface.

Enzyme immobilization studied through molecular dynamic simulations

“…Additionally, Zhuang et al (2020) observed that the lipase immobilized on functionalized GO is around 20 times more active than when immobilized on GO. Regarding the effect of GO on enzyme stability, Li et al (2021) showed that the thermal stability of D-psicose 3-epimerase (DPEase) enzyme is improved upon immobilization. Aiming to rationalize this effect all atom MD simulations of DPEase complexed with its natural substrate D-Fructose were performed with and without anchoring to GO.…”