AMBER TI Tutorials
Contents
A simple TIMD tutorial about T4-lysozyme
Introduction to TIMD
This is a TIMD tutorial based on the tutorial written by Thomas Steinbrecher on the site[1]. But some important changes have been made to suit the current AMBER 10 version according to Miranda's tutorial from Simmerling's lab[2].
In this tutorial, free energy calculations will be used to calculate the relative binding free energy of two simple ligands, benzene and phenol to the T4-lysozyme mutant L99A. Free energies will be computed by using the thermodynamic integration facilities of the sander program. A modified van-der-Waals equation (softcore potentials) are used to ensure smooth free energy curves.
Thermodynamic cycle and Method
TI calculations compute the free energy difference between two states A and B by coupling them via a parameters λ that serves as an additional, nonspatial coordinate. This λ formalism allows the free energy difference between the states to be computed as:
