On the Biological Advantage of Chirality

The presence of chirality in the main molecules of life may well be not just a structural artifact, but of pure biological advantage. The possibility of the existence of a phenomenon of a special mode of interaction, labeled as " chiral interaction " (CI), for which structural chirality is a necessary condition , is the main reason for such an advantage. In order to demonstrate such a possibility, macroscopic chiral devices are introduced and presented as analogies for such an interaction. For this purpose it is important to make a clear distinction between geometric and physical chiralities, where the latter are capable to perform chiral interactions with various media. Apart from chirality, a few other structural elements are required. In particular, the presence of an interface that separates between the chiral device and the 1 medium with which it is interacting. The physical chirality is build into this very interface where chiral interaction is taking place. On a molecular level, soluble proteins in particular, the active medium is the presence of random ionic motion in the aqueous solvent. As a result of chiral interaction a certain perturbation, or current, is generated and flowing along the coils of α-helix structure in one preferred direction out of two possible ones. A model for such a chiral interaction is presented and a few significant consequences are pointed out. In particular, it is important to emphasize the time-irreversible feature of chiral interaction, which leads to its non-ergodic nature that is to be considered a necessary condition for evolutionary processes in biomolecules. As yet there exists no direct experimental evidence for the validity of chiral interaction on a molecular level, but there are quite a few indirect supporting evidences. In particular, there exists an experimental result by Careri et al. who found a clear linkage between the free protonic motion in the hydration layer of proteins and their enzymatic activity. A few direct experiments for verifying the validity of chiral interaction on molecular level are proposed hereby for hydrophobic amino acids at the water-air interface, where chiral interaction may take place. Among these there is also a new approach of applying a SQUID to detect a weak magnetic field that is associated with the chiral interaction effect. If proven right, chiral interaction may open new approaches and possibilities for better understanding of the rather complex autocatalytic function of soluble proteins.