The implementation of multiconfigurational quantum chemistry methods into a quantum-mechanics/molecular-mechanics protocol has allowed the construction of a realistic computer model for the sensory rhodopsin of the cyanobacterium Anabaena PCC 7120. The model, which reproduces the absorption spectra of both the all-trans and 13-cis forms of the protein and their associated K and L intermediates, is employed to investigate the light-driven steps of the photochromic cycle exhibited by the protein. It is found that the photoisomerizations of the all-trans and 13-cis retinal chromophores occur through unidirectional, counterclockwise 180° rotations of the ! C14 " C15 ! moiety with respect to the Lys210- linked end of the chromophore axis. Thus, the sequential interconversions of the all-trans and 13-cis forms during a single photochromic cycle yield a complete (360°) unidirectional rotation of the ! C14 " C15 ! moiety. This finding implies that Anabaena sensory rhodopsin is a biological realization of a light-driven molecular rotor.

Strambi, A., Durbeij, B., Ferré, N., & Olivucci, M. (2010). Anabaena sensory rhodopsin is a light-driven unidirectional rotor. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 107(50), 21322-21326 [10.1073/pnas.1015085107].

Anabaena sensory rhodopsin is a light-driven unidirectional rotor

OLIVUCCI, MASSIMO
2010

Abstract

The implementation of multiconfigurational quantum chemistry methods into a quantum-mechanics/molecular-mechanics protocol has allowed the construction of a realistic computer model for the sensory rhodopsin of the cyanobacterium Anabaena PCC 7120. The model, which reproduces the absorption spectra of both the all-trans and 13-cis forms of the protein and their associated K and L intermediates, is employed to investigate the light-driven steps of the photochromic cycle exhibited by the protein. It is found that the photoisomerizations of the all-trans and 13-cis retinal chromophores occur through unidirectional, counterclockwise 180° rotations of the ! C14 " C15 ! moiety with respect to the Lys210- linked end of the chromophore axis. Thus, the sequential interconversions of the all-trans and 13-cis forms during a single photochromic cycle yield a complete (360°) unidirectional rotation of the ! C14 " C15 ! moiety. This finding implies that Anabaena sensory rhodopsin is a biological realization of a light-driven molecular rotor.
File in questo prodotto:
File Dimensione Formato  
Strambi Proceedings of the National Academy of Sci #2.pdf

non disponibili

Tipologia: Post-print
Licenza: NON PUBBLICO - Accesso privato/ristretto
Dimensione 890.36 kB
Formato Adobe PDF
890.36 kB Adobe PDF   Visualizza/Apri   Richiedi una copia

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11365/8047
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo