1. Could you explain the significance of your article to the non-specialist?

Our work implies that the violation of parity, known to be extremely weak, not only sticks its mark in the molecular area but further propagates through selective interaction with water into biology, and may have even played a role in the origin of life. Does it also play a mysterious role in our consciousness?

Biological molecules possess a one-sided asymmetrical configuration, termed "chirality", while their mirror image molecules are almost completely excluded from biological systems. Why has evolution selected molecules of one type and rejected its mirror image which is absolutely identical in its physical and chemical properties? Was it merely accidental? or a preferred selection? These questions are still at the center of heated scientific debates. 

In our work we addressed this riddle with a unique system and discovered that, unexpectedly, there is an inherent physico-chemical preference towards one symmetry over its mirror image. The implications of our finding are far reaching. We propose that the asymmetrical weak nuclear force, with the help of water, propagates to the molecular milieu to build up a one-sided asymmetrical population which provided the molecular building stones of biology. 

 

2. What has motivated you to conduct this work?

Classically speaking, chiral isomers are perfectly identical in their bulk physical and chemical properties. However, all through the scientific literature one can find claims on unexpected small, yet questionable, differences between chiral isomers, mostly in the condense form, like supersaturated solutions, crystals, micellar aggregates etc. These were left undealt with, in particular due to the suspicion that they could have emerged from the presence of undetectable impurities. However, earlier in 1993 ( J. Am. Chem. Soc. 115, 12545), we observed a profound difference in surface organization in micelles made of the two chiral isomers of amino acid derivatives. The observed difference was much too strong to be accounted for by an experimental flow. This has convinced us that there is an inherent preference between the chiral isomers of amino acids, which I believe, has been clearly demonstrated in our current paper.

 

3. Where do you see this work developing in the future?

We realize the controversial aspect of our work and expect massive pro and con reactions. The direction that we plan to take in future research is in comparing structures and catalytic activity of enantiomeric peptides and micelles.

The trivial explanation of our results that light water contains trace quantities of an unknown contaminant which somehow produced the differences we observed is quite unlikely. First, our poly peptide systems were a priori selected for this study to eliminate the effects of putative impurities. Secondly, in most of our experiments with heavy water, where the differences were virtually eliminated, 20% of light water was still present. Our hypothesis on the involvement of spin isomers of water in the mechanism of chiral enhancement is novel and as such should be confirmed by further experimental and computational analyses.

 

4. Are there any particular challenges facing future research in this area?

The ultimate challenge invoked by our work is the possibility that the function of a putative mirror image biological system (D-amino-acids, L-saccharides, etc.) would be "inferior" to its natural enantiomeric system. For example, one may ask: is the activity of a hydrolytic enzyme made of D amino acids and reacting on a D substrate different (or identical) to that of its entantiomeric natural system?  Obviously, at the current state of the art simpler systems, like micellar aggregates, can serve as good models in this direction.