C´ deviation-a more obvious method for description of amino acid geometry

A new method for the description of amino acid geometry, C´ deviation is proposed in this paper. Because of the three dimension coordinates of atoms are shown on the graph, this method is more obvious than conformation angles used before. The structural diversity could be evaluated by calculating the distance between two farthest points in the C´ scatter plot. This method would be a valuable tool for the study on the structural diversity of the identical amino acids in peptide fragments.