Evidence for new enantiospecific interaction force in chiral biomolecules

Enantiospecific biorecognition interactions are key to many biological events. Commonly, bio-affinity values, measured in these processes, are higher than those calculated by available methods. We report here the first direct measurement of the interaction force between two chiral peptides (right- and left-handed helical polyalanine peptides) and the quantification of difference in the interaction force between homochiral and heterochiral pairs of molecules using atomic force microscope (AFM), together with supportive calculations based on a simple theoretical model. A force difference of 70 pN between same and opposite enantiomer interactions is measured. Additional measurements show spin dependency and fast decay of the interaction term, consistent with spin exchange interactions. This short range enantiospecific interaction term is especially relevant in crowded biological systems. The results shed light on the importance of spin and exchange interactions in biological processes.

Automated summary

Enantiospecific biorecognition interactions play a key role in biological events, with bio-affinity values often higher than predicted. This study presents the first direct measurement of interaction forces between chiral peptides, showing a force difference of 70 pN between same and opposite enantiomer interactions. Spin dependency and fast decay of the interaction term suggest the importance of spin and exchange interactions in biological processes.