Origins of biomolecular handedness.
Classical mechanisms proposed for the transition from racemic geochemistry to homochiral biochemistry in terrestrial evolution generally ascribe to chance the particular handed choice of the L-amino acids and the D-sugars by self-replicating systems. The parity-violating weak neutral current interaction gives rise to an energy difference between a chiral molecule and its mirror-image isomer, resulting in a small stabilization of the L-amino acids and the L-peptides in the alpha-helix and the beta-sheet conformation relative to the corresponding enantiomer. The energy difference suffices to break the chiral symmetry of autocatalytic racemic reaction sequences in an open non-equilibrium system.
D000596:Amino Acids; D000818:Animals; D002241:Carbohydrates; D055598:Chemical Phenomena; D002621:Chemistry; D007700:Kinetics; D008968:Molecular Conformation; D011487:Protein Conformation; D011506:Proteins; D013237:Stereoisomerism
D000596:Amino Acids; D002241:Carbohydrates; D011506:Proteins