Vector Model of Chiral-Induced Spin Selectivity in Photoinduced Charge-Separations of Cryptochrome for Magnetoreception

On the "radical-pair-based magnetic compass", mechanisms of the Earth magnetic field sensing are actively debated at molecular levels based upon spin multiplicity-induced reaction selectivity. On this, much remains unknown about how chirality-induced spin selectivity (CISS) alters the magnetic compass effect. We observed electron spin polarization of the long-range chargeseparated states in cryptochrome using time-resolved electron paramagnetic resonance. Minor effects of CISS on the spin polarization have been clarified. We herein propose that these CISS contributions originate from conformation rearrangements in oxidized tryptophane residues, attributable to reported structural variations between the active and inactive states of the flavoproteins by blue light irradiations. It has also been predicted that even the minor CISS can create a large yield anisotropy and specific directionality of the signaling state due to a violation of the field-inversion symmetry, which would thus serve as a potential contribution to the chemical compass sensory mechanism.