We present an ab-initio molecular dynamics study of a model of the chromophore of rhodopsin. The 11-cis to all-trans ground-state isomerization of a retinylidene-ethylimine.HCl has been induced by applying an external classical force field to the C10-C11-C12-C13 dihedral angle, in addition to the ab-initio forces. By using this hybrid approach, we find that the transition state is characterized by a well-defined bond pattern along the chromophore and by a positive charge displacement. The relaxation of the chromophore is associated with propagation of a conjugation defect that transports the excess positive charge along the backbone. (C) 1998 published by Elsevier Science B.V. All rights reserved.
The transition state in the isomerization of rhodopsin
La Penna G;
1998
Abstract
We present an ab-initio molecular dynamics study of a model of the chromophore of rhodopsin. The 11-cis to all-trans ground-state isomerization of a retinylidene-ethylimine.HCl has been induced by applying an external classical force field to the C10-C11-C12-C13 dihedral angle, in addition to the ab-initio forces. By using this hybrid approach, we find that the transition state is characterized by a well-defined bond pattern along the chromophore and by a positive charge displacement. The relaxation of the chromophore is associated with propagation of a conjugation defect that transports the excess positive charge along the backbone. (C) 1998 published by Elsevier Science B.V. All rights reserved.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
