MOLECULAR-DYNAMICS SIMULATION OF THE PROLINE CONFORMATIONAL EQUILIBRIUM AND DYNAMICS IN ANTAMANIDE USING THE GROMOS FORCE-FIELD

Molecular dynamics simulations of the proline-containing cyclic peptid e antamanide using the GROMOS force field have been performed in order to compare the conformational equilibrium and dynamics of the four pr oline residues with experimental data originating from NMR spectroscop y. J-coupling constants, order parameters, and conformational populati ons are well-reproduced. The average simulated conformational residenc e times of 4 ps are shorter than the measured ones which are on the or der of 30 ps, implying a somewhat too flexible force field for proline rings. The proline dynamics seems to be insensitive to the observed c onformational dynamics of the peptide ring and to the solvent viscosit y.