The parity violating energy differences between the enantiomers of α-amino acids

Abstract

The parity-violating weak neutral current perturbation of the groundstate electronic energy has been calculated, using ab initio methods, for the series of α-amino acids glycine, alanine, valine, serine and aspartic acid. It is found that the WNC energy shifts for these fundamental biomolecules consistently favour the existence of the natural L-enantiomers in preference to the unnatural mirror image D-enantiomers for the molecular conformations preferred in aqueous media. The parity violating energy differences between enantiomers are small, of the order 10-14 J mol-1, and highly sensitive to molecular conformation. The significance of the energy difference between enantionmers arising from the electroweak interactions with reference to the transition from a prebiotic racemic geochemistry to the terrestrial homochiral biochemistry is discussed.