Potential energy surface and kinetics of the helix-coil transition in a 33-peptide

The CHARMM force field is used to calculate 36 minima along the potential energy surface of the helix -coil conversion of Ac-A14KG3A14K + 2H+ and to interconnect them through 35 transition states. The energy barriers are used to give the rate constants of interconversion between the conformers and the relevant kinetic equations are then solved. Fair to good agreement with the data obtained by drift time spectrometry experiments (D. T.Kaleta,M. F. Jarrold, J.Am.Chem. Soc . 125:7186, 2003) is obtained under a simple hypothesis of the initial conformer distribution.