Studies Of The Role Of Disulfide Bonds In The Stability Of Protein Materials By Molecular Dynamics Simulations

Protein materials are a hot interdisciplinary research topic,which contains nanotechnology,chemical engineering and biology engineering.This field is often integrated in hierarchical patterns link the nanoscale to larger length and time scales.In this area,disulfide bonds play an important role in maintaining the stability of the protein material.The understanding of the role of disulfide bonds in protein material is a pivotal subject in protein material engineering.Recently,researchers have investigated the effects of disulfide bonds in protein materials both experimentally and computationally.For further study of the disulfide bonds,in this study,molecular dynamics(MD)simulations were used within a short time of 100 ns to study and compare the conformational changes of the wild type form with the reduced form of the protein,where the cysteine residues that formed the disulfide bonds were removed.However,an important issue is that upon the removal of residues,besides the effect of elimination of disulfide bonds,the removal of residues itself is also expected to affect the protein conformation.To determine which effect plays a critical role in affecting the conformation within the short simulation time,we take three types of proteins—ginkbilobin-2,human prion protein and human serum albumin—as examples.The results show that the conformational changes of the protein materials in the short simulation time stem from the removal of residues rather than the elimination of the disulfide bond.Moreover,we take human prion protein and ginkbilobin-2 as examples to study the effect of the disulfide bond on the stability of the protein material at a larger time scale,using the steered MD simulation method.The results show that by the elimination of the effect of the disulfide bond,the protein material becomes much less unstable,with the lifetime of about 17 ?s.The presence of the disulfide bonds can significantly enhance the stability of the protein material at different degrees.