The effect of the neglect of electronic polarization in peptide folding simulations

The effect of the neglect of electronic polarization, on the relative stability of different conformations of a model peptide in a nonpolar environment, has been investigated. Configurations generated in molecular dynamics simulations of polyalanine (ACE-ALA₁₅-NH₂) in cyctohexane were analyzed in terms of a nonmutual polarization model. The work clearly demonstrates that the stability of conformations which have an enhanced electric field, such as is generated by the formation of a helix dipole, can be significantly underestimated by the neglect of the effects of electronic polarization in weakly polar or nonpolar solvents.