Molecular orbital calculations on polypeptides and proteins. Part II. Stability and conformational structure of cis-dipeptides

Abstract

The extended Hückel theory has been used to investigate the relative stabilities of cis- and trans-dipeptides. In general, trans-peptides are predicted to have a greater stability. The conformational structure of poly-L-proline I, in which the peptide bonds are in the cis configuration, is also explained by this theory. The results have been compared with those obtained from the contact criterion.