  Protein folding processes are generally described statistically with the help
of multidimensional free energy landscape, typically reduced to a 1-D free
energy profile along good reaction co-ordinate. There are many physical
parameters which are responsible for protein molecule to hop between the native
and unfolded states. The transition path region across the barrier is the
region corresponding to the minimum fluctuation. The extent to which this
transition region can extend beyond the obvious 1/2 kBT region has been a
question of interest for a long time. We propose a new method to locate this
transition path region and to study its dependence on the asymmetry of the
transition state for a given free energy landscape. We have performed Brownian
dynamics simulations with Gaussian white noise and Monte-Carlo simulation by
sampling ten thousand successful transitions across the barrier for three
different energy landscape having fixed barrier height with asymmetry in their
curvatures. It was found that the transition path region increases with the
increase in the asymmetry of the energy landscape in the transition region. The
rate limiting parameter diffusion constant over the diffusive barrier, rate
constant at particular force and transition path time for different potentials
were estimated directly from the landscape profile using Kramers theory for
diffusive barrier crossing. It was also found that the average diffusion in the
native state increases with the increase in the asymmetry of the transition
state towards the non-native state.
