Possible role of the 11-
            <i>cis</i>
            -retinyl conformation in controlling the dual decay processes of excited rhodopsin

Liu, Robert S. H.; Hammond, George S.; Mirzadegan, Taraneh

doi:10.1073/pnas.0501665102

Cited by 10 publications

(5 citation statements)

References 31 publications

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“…The ultrafast dynamics of the present systems is reminiscent of that of many biological molecules for which the isomerization routes are mainly governed by conformation distribution of caged guest and for which several mechanisms have been proposed. For example, the observed two decay processes of excited 11-cis-retinal in rhodopsin were suggested because of excitation of two different ground-state rotamers of the retinal chromophor that fit within the binding cavity (44), shown by x-ray crystal structure (38,39). A few years ago, Kandori et al (40) proposed a model for the photodynamics of rhodopsin involving two different fluorescent species.…”

Section: Femtochemistry In Solutionmentioning

confidence: 99%

See 1 more Smart Citation

Femtochemistry of orange II in solution and in chemical and biological nanocavities

Douhal

Sanz

Tormo

2005

Proc. Natl. Acad. Sci. U.S.A.

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In this work, we report on studies of the nature of the dynamics and hydrophobic binding in cyclodextrins and human serum albumin protein complexes with orange II. With femtosecond time resolution, we examined the proton-transfer and trans-cis isomerization reactions of the ligand in these nanocavities and in pure solvents. Because of confinement at the ground state, the orientational motion in the formed phototautomer is restricted, leading to a rich dynamics. Therefore, the emission lifetimes span a large window of tens to hundreds of picoseconds in the cavities. Possible H-bond interactions between the guest and cyclodextrin do not affect the caged dynamics. For the protein-ligand complexes, slow diffusional motion (Ϸ630 ps) observed in the anisotropy decay indicates that the binding structure is not completely rigid, and the embedded guest is not frozen with the hydrophobic pocket. The ultrafast isomerization and decays are explained in terms of coupling motions between N-N and C-N stretching modes of the formed tautomer. We discuss the role of confinement on the trans-cis isomerization with the cavities and its relationships to frequency and time domains of nanostructure emission.cyclodextrins ͉ protein ͉ H-bond ͉ twisting ͉ anisotropy F emtosecond (fs) studies of caged molecules in nanocavities provide direct information on the relationship between time and space domains of molecular relaxation (1). Therefore, simple and complex (in concept) molecular systems have been studied using cyclodextrins (CDs), proteins, micelles, pores, and zeolites as nanohosts, demonstrating the confinement effect of the hydrophobic nanocavities on the spectroscopy and dynamics of the guests (2-13). Relevant information on the ultrafast dynamics of caged wavepackets involving breaking͞making chemical bonds, and solvation has been acquired.Orange II (OII) (Fig. 1), also called acid orange 7, is a molecule that has O-H . . . N and NAN bonds and may show photoinduced intramolecular proton-transfer (IPT) and transcis isomerization reactions. It is widely used in the dyeing of textiles, food, and cosmetics and thus is found in the wastewaters of the related industries (14). It has been reported that it exists under azoenol (AZO) and ketohydrazone (HYZ) forms (Fig. 1) (15-20). In a water solution, for example, the H-atom within the O-H . . . N intramolecular H-bond is shifted to the nitrogen site, making HYZ structure the most stable one (Ϸ95%) (20). In DMSO, the HYZ population decreases to 70%, and in solid state it becomes the only populated structure (20). Recent x-ray studies of phenyl substituted 1-(arylazo)-2-naphthols showed that this kind of molecules displaying HYZ-AZO tautomerism can form intramolecular resonance-assisted H-bonds from pure N-H . . . O to pure N . . . H-O structures, depending on the phenyl derivative (21, 22). Furthermore, a recent photophysical study of similar molecules in solution has shown the occurrence of a photoinduced proton-transfer reaction in AZO to give HYZ structure with a very low emission qu...

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Section: Femtochemistry In Solutionmentioning

confidence: 99%

“…1). We believe that the present work shines more light on the photodynamics of OII, and the results might be used for a better understanding of other systems undergoing isomerization reactions like retinal rhodopsin (38)(39)(40)(41)(42)(43)(44). trophotometers, respectively.…”

mentioning

confidence: 99%

Femtochemistry of orange II in solution and in chemical and biological nanocavities

Douhal

Sanz

Tormo

2005

Proc. Natl. Acad. Sci. U.S.A.

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“…An extended interpretation of the primary events in the Rh photochemical cycle is presented, which differs from the standard 3 and the branch models 6, 32. Our results suggest a more complex than expected scenario where the triplet state, usually ignored in deciphering the early events of the photoinduced isomerization of Rh, may play a role.…”

Section: Discussionmentioning

confidence: 57%

On the role of the triplet state in the cis/trans isomerization of rhodopsin: A CASPT2//CASSCF study of a model chromophore

González‐Luque

Olaso‐González

Merchán

et al. 2011

Int J of Quantum Chemistry

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ABSTRACT:The possibility of population of the lowest-lying triplet state (T 1 ) in the early events of the photochemical isomerization process of a model chromophore of Rhodopsin (Rh) has been analyzed using multireference perturbation theory (CASPT2//CASSCF) methods. It is shown that the characteristics of the isomerization process namely small S 1 ÀT 1 gap, presence of hydrogen out of plane active vibrational modes, and existence of a dense manifold of vibrational states, render possible the fulfilment of the conditions needed for the population of T 1 . The possible consequences for the photochemistry and photophysics of Rh are also discussed.

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“…56 The latter refl ects exquisitely clever supramolecular effects of opsin on the structure and reactivity of the fl exible 11 -cis -retinyl chromophore. 56,59 …”

Section: In Crystalsmentioning

confidence: 99%

Supramolecular Effects on Mechanisms of Photoisomerization: Hula Twist, Bicycle Pedal, and One‐Bond‐Flip

Liu

Yang

Zhao

et al. 2011

Supramolecular Photochemistry

Self Cite

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Photoisomerization in the form of interconversion of the cis and trans isomers around a double bond is the key triggering process for many photosensitive biopigments. 1 They include the visual pigment rhodopsin, the proton pumping bacteriorhodopsin (bR), the phototaxis of photoactive yellow protein (PYP), the seed -germinating trigger protein phytochrome, and many other related pigments. Much spectroscopic and chemical effort has gone into elucidation of the primary processes and products associated with these important pigments. These efforts along with photochemical and theoretical work with simple organic systems 2 have led to improved understanding of mechanisms of photoisomerization, often controlled by host molecules in dictating the exact mechanism participating in a given system. In this chapter, an attempt is made to review medium -controlled photoisomerization processes and to provide an overview of different types of mechanisms that take place in nature and under laboratory conditions. Ever since the fi rst picosecond time -resolved spectroscopic study on events revealing the rapid isomerization following photoexcitation of the visual 547 547 Supramolecular Photochemistry: Controlling Photochemical Processes, First Edition. Edited by V. Ramamurthy and Yoshihisa Inoue.

show abstract

Possible role of the 11- cis -retinyl conformation in controlling the dual decay processes of excited rhodopsin

Cited by 10 publications

References 31 publications

Femtochemistry of orange II in solution and in chemical and biological nanocavities

Femtochemistry of orange II in solution and in chemical and biological nanocavities

On the role of the triplet state in the cis/trans isomerization of rhodopsin: A CASPT2//CASSCF study of a model chromophore

Supramolecular Effects on Mechanisms of Photoisomerization: Hula Twist, Bicycle Pedal, and One‐Bond‐Flip

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