PEPTIDES AND PEPTOIDS - A SYSTEMATIC STRUCTURE COMPARISON

A systematic analysis of the conformational space of the basic structu re unit of peptoids in comparison to the corresponding peptide unit wa s performed based on ab initio MO theory and complemented by molecular mechanics (MM) and molecular dynamics (MD) calculations both in the g as phase and in aqueous solution. The calculations show three minimum conformations denoted as C-7 beta, a(D) and a that do not correspond t o conformers on the gas phase peptide potential energy hypersurface. T he influence of aqueous solvation was estimated by means of continuum models. The MD simulations indicate the a(D) form as the preferred con formation in solution both in cis and trans peptide bond orientations.