CHIRAL DISCRIMINATION - A MODEL FOR THE INTERACTION BETWEEN A HELICOIDAL SYSTEM AND AN AMINO-ACID MOLECULE

The interaction between a helix characterized by its radius, its pitch and the atomic distribution inside its monomer and of an amino acid molecule is determined on the basis of semi-empirical potentials including Lennard-Jones, electrostatic, induction and hydrogen bond contributions. Calculations are performed for various values of the helix characteristics which schematize helicoidal polysaccharides (cellulose, cellulose derivatives, ...) or chiral cavities (cyclodextrin). The helix configuration acts as a chiral revealer as it freezes the amino acid inside its cavity. The chiral discrimination of D and L amino acids is about 2-5% of the total interaction for most of the helix geometries and it can reach 8% when the amino acid lies inside the helix.