Validation of the GROMOS 54A7 Force Field Regarding Mixed <i>α</i>/<i>β</i>‐Peptide Molecules

Abstract

Abstract A molecular‐dynamics (MD) simulation study of two heptapeptides containing α ‐ and β ‐amino acid residues is presented. According to NMR experiments, the two peptides differ in dominant fold when solvated in MeOH: peptide 3 adopts predominantly β ‐hairpin‐like conformations, while peptide 8 adopts a 14 / 15 ‐helical fold. The MD simulations largely reproduce the experimental data. Application of NOE atomatom distance restraining improves the agreement with experimental data, but reduces the conformational sampling. Peptide 3 shows a variety of conformations, while still agreeing with the NOE and 3 J ‐coupling data, whereas the conformational ensemble of peptide 8 is dominated by one helical conformation. The results confirm the suitability of the GROMOS 54A7 force field for simulation or structure refinement of mixed α / β ‐peptides in MeOH.