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Un cambio de opsina en la rodopsina: excitación S0-S1 de la retina en la proteína, en la solución y en la fase
Ksenia Bravaya1, Anastasia Bochenkova, Alexander Granovsky
1Department of Chemistry, M.V. Lomonosov Moscow State University, 1/3, Leninskie Gory, Moscow 119992, Russian Federation.
Journal of the American Chemical Society
|October 11, 2007
Resumen
Los modelos computacionales predicen con precisión los espectros de fotoabsorción de la retina 11-cis en varios entornos. Los factores clave que influyen en los espectros incluyen la geometría de los cromóforos y las interacciones de las proteínas, cruciales para comprender los procesos visuales.
Área de la Ciencia:
- Química computacional es la química computacional.
- La fotoquímica es la fotoquímica.
- La biofísica es la biofísica.
Sus antecedentes:
- 11-cis retinal es un cromóforo clave en la visión.
- Comprender su fotoabsorción es vital para la función del pigmento visual.
Objetivo del estudio:
- Para modelar y analizar la fotoabsorción de 11-cis retinal.
- Investigar la influencia de diferentes ambientes (gas, solución, proteína) en sus espectros.
Principales métodos:
- El enfoque mecánico cuántico-mecánico molecular (QM/MM).
- Teoría de la perturbación de cuasi degeneración multiconfiguracional aumentada (aug-MCQDPT2).
- Teoría funcional de densidad (DFT) PBE0/cc-pVDZ para la optimización de la geometría.
Principales resultados:
- Las bandas de absorción computarizadas coinciden con los datos experimentales en entornos de gas, solución y proteína.
- Geometría de cromóforo no plana identificada en proteínas debido a Glu181.1.
- El campo proteico afecta significativamente el orden de enlace C11-C12 tras la excitación.
Conclusiones:
- Los modelos computacionales reproducen con precisión los espectros de fotoabsorción experimentales.
- La geometría de los cromóforos, los campos electrostáticos y los contadores son fundamentales para las propiedades espectrales.
- El entorno de las proteínas, particularmente los residuos cargados, dicta la no planaridad e influye en la especificidad de la fotoisomerización.
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