Evidence for new enantiospecific interaction force in chiral biomolecules

•Enantiospecific interactions are probed using a functionalized AFM cantilever•A force difference of 70 pN between homo- and heterochiral pairs is obtained•The directional resulting from transient spin exchange interactions•Toy model calculations reveal the short range directionality Most biological molecules chiral. Interestingly, in life, they appear one chirality. This not trivial as most non-biological chemistry achiral. Indeed, earliest evidence for amino acids on earth suggests that both enantiomers were present. One driving forces to preserve homochirality life may be enantiomer-specific forces. Here, interaction chiral peptides molecule atomic microscope. The results show same-handed (chirality) polypeptides generate large attraction potentials (?10 Kcal/mol), agreement with simulations. force, related chiral-induced selectivity (CISS) effect, ranged therefore especially relevant crowded systems. places symmetry constraints protein folding, it provide reason preserving chirality life. For applications, these promote simulations enabling improve synthesis. Enantiospecific biorecognition key many events. Commonly, bio-affinity values, measured processes, higher than those calculated by available methods. We report here first direct measurement two (right- left-handed helical polyalanine peptides) quantification homochiral microscope (AFM), together supportive based simple theoretical model. A same opposite enantiomer measured. Additional measurements dependency fast decay term, consistent interactions. enantiospecific term shed light importance processes. 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