CHARGE LOCALIZATION AND DYNAMICS IN RHODOPSIN

We present a Car-Parrinello ab initio molecular dynamics study of the retinylidene chromophore of rhodopsin, the membrane protein involved i n the primary event in vision. We observe a coherent propagation of a conjugation defect associated with charge transport along the chromoph ore conjugated backbone. This solitonlike charge propagation is strong ly coupled to the vibrational degrees of freedom due to the nonplanari ty of the molecule. The implications for the chromophore isomerization mechanism are discussed.