Extended Hückel MO calculations of the conformation of several amino acids

Abstract

The conformation of the amino acid residues, glycine, alanine, proline, and phenylalanine have been predicted from molecular orbital calculations of appropriate model compounds. Using the current main chain rotation convention (Φ, ψ) the principle conformations were found to be glycine (0‡, 0‡), alanine (240‡, 240‡), proline (120‡, 330‡) and phenylalanine (30‡, 330‡). Several secondary conformations were also found for glycine. A comparison of the predicted conformations is in good agreement with experimental data on comparable residues or model compounds.