Conformational analysis of the simplest chiral pseudo-peptide and selectedderivatives

Conformational properties of three model pseudo-peptides were investigated by semi-empirical and ab initio MO methods. The three simplest model pseudo -peptides included the protonated form of N-formyl pseudo-alanineamid HCONH -CHMe-CH2NH3+, N-formyl pseudo-alanine itself HCONH-CHMe-CH2NH2. as well as the formylated N-formyl pseudo-alanine (i.e. propylene-di(N-formylamine)) HCONH-CHMe-CH2NHCOH. It was shown that geometries of the pseudo-peptides in their global minima were determined by H-bonds. From the computated result s, it follows that in general pseudo-peptides can mimic the backbone of the parent peptides. These computational results are in full agreement with pr eviously reported experimental data. N-formyl pseudo-alanine was shown to b e more flexible, than the parent peptide. (C) 2000 Elsevier Science B.V. Al l rights reserved.