Electron density deformations provide new insights into the spectral shift of rhodopsins

Authors

  • Erix Wiliam Hernández-Rodríguez,

    1. Departamento de Bioquímica, Instituto de Ciencias Básicas y Preclínicas“Victoria de Girón, ” Universidad de Ciencias Médicas de La Habana, Havana, Cuba
    2. Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
    3. Laboratorio de Química Computacional y Teórica, Departamento de Química Física, Universidad de La Habana, Havana, Cuba
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  • Ana Lilian Montero-Alejo,

    1. Laboratorio de Química Computacional y Teórica, Departamento de Química Física, Universidad de La Habana, Havana, Cuba
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  • Rafael López,

    1. Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
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  • Elsa Sánchez-García,

    1. Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, Mülheim an der Ruhr, Germany
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  • Luis Alberto Montero-Cabrera,

    1. Laboratorio de Química Computacional y Teórica, Departamento de Química Física, Universidad de La Habana, Havana, Cuba
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  • José Manuel García de la Vega

    Corresponding author
    • Departamento de Química Física Aplicada, Facultad de Ciencias, Universidad Autónoma de Madrid, Madrid, Spain
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E-mail: garcia.delavega@uam.es

Abstract

Spectral shifts of rhodopsin, which are related to variations of the electron distribution in 11-cis-retinal, are investigated here using the method of deformed atoms in molecules. We found that systems carrying the M207R and S186W mutations display large perturbations of the π-conjugated system with respect to wild-type rhodopsins. These changes agree with the predicted behavior of the bond length alternation (BLA) and the blue shifts of vertical excitation energies of these systems. The effect of the planarity of the central and Schiff-base regions of retinal chain on the electronic structure of the chromophore is also investigated. By establishing nonlinear polynomial relations between BLA, chain distortions, and vertical excitation energies, we are also able to provide a semiquantitative approach for the understanding of the mechanisms regulating spectral shifts in rhodopsin and its mutants. © 2013 Wiley Periodicals, Inc.

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