| 초록 |
We have used a simple lattice model of protein and denaturant in order to investigate the effect of denaturant on protein folding or unfolding transition. Using the histogram analysis and Monte Carlo simulation, we calculated the free energy of unfolding as a function of denaturant concentration varying the binding energy between protein and denaturant molecule. Our primary results show that for the binding energies stronger than the average contact energy of protein, the free energy of unfolding is linearly dependent upon the denaturant concentration as observed in the urea-induced unfolding experiments. Furthermore, we have investigated the effect of long-ranged interactions on the free energy of unfolding to understand the role of electrostatic nature of denaturants possessing ions such as guanidinium hydrochloride. The simulation results show that due to the long-ranged interactions the concentration dependence of the free energy of unfolding is no longer linear, indicating that linear extrapolation method for determination of free energy of unfolding in the absence of denaturant is not applicable for denaturant-induced unfolding reactions involving electrostatic interactions. |
