Electron Spin-Polarizability and Charge Dynamics in Ancient Polypeptides – Their Role in Protein Function

Abstract Primitive nucleic acids and peptides likely collaborated during the earliest stages of biochemistry. What forces drove their interactions, and how did these forces shape the properties of primitive complexes? We investigated the association of two model primordial polypeptides with DNA. Coupling the peptides to a ferromagnetic substrate results in a dependence of the association rate and the extent of DNA binding on the orientation of magnetic moment of the substrate. The DNA binding could be nearly abolished by inverting the orientation of the magnetic field, despite the two polymers having complementary net charges. Inverting the chirality of either the entire peptide or just the connecting cysteine residue inverted the effect of the magnetic moment orientation. These results are attributed to the chiral-induced spin selectivity (CISS) effect, in which molecular chirality and electron spin interact to alter the electric polarizability of the protein. The observation of CISS effects governing simple protein-DNA complexes, suggests that this phenomenon was plausibly operative and potentially significant for primitive biomolecules. A key consequence of the CISS effect is to increase the kinetic stability of primitive protein-nucleic acid complexes. Taken together, our results show how emergent phenomena due to chirality and spin enhance bio-association.