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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
15
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pubmed:dateCreated |
1989-11-22
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pubmed:abstractText |
Primary photochemical behaviors of cattle rhodopsin analogues (Rh5 and Rh7) having cyclopenta- and cycloheptatrienylidene 11-cis-locked retinals (Ret5 and Ret7, respectively) were studied by excitation with a picosecond laser pulse (wavelength 532 nm; duration 21 ps). Picosecond absorption and fluorescence measurements of Rh5 showed formation of only a long-lived excited singlet state (tau l/e = 85 ps). The excited state of the retinal analogue having a five-membered ring was stabilized in protein (Rh5) more than in solvent (protonated Schiff base of Ret5; PSB5). Excitation of Rh7 produced two ground-state photoproducts, Rh7 (580) and Rh7 (630). According to the analysis of photon density dependency, Rh7 (580) was a single-photon product of Rh7, while Rh7 (630) was the photoproduct of Rh7 (580). Fluorescence emitted from a seven-membered ring system like Rh7 or a protonated Schiff base of Ret7 (PSB7) was weaker than that in a corresponding five-membered ring system, especially in protein (Rh7). The difference in photoreaction between Rh5 and Rh7 may originate from the difference in fixation of the 11-cis form. On the basis of the spectral and kinetic similarities between Rh7 (580) and photorhodopsin, a precursor of bathorhodopsin, it was proposed that both have twisted all-trans chromophores in the way of the isomerization. The protein moiety of rhodopsin which fixes the chromophore at both ends seems to accelerate the rotation of the C11-C12 double bond and to prevent it from going through relaxation processes other than the isomerization. This may be a plausible reason why rhodopsin has a large quantum yield (0.67).
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pubmed:grant | |
pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical | |
pubmed:status |
MEDLINE
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pubmed:month |
Jul
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pubmed:issn |
0006-2960
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
25
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pubmed:volume |
28
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
6460-7
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pubmed:dateRevised |
2008-11-21
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pubmed:meshHeading |
pubmed-meshheading:2790007-Animals,
pubmed-meshheading:2790007-Cattle,
pubmed-meshheading:2790007-Isomerism,
pubmed-meshheading:2790007-Kinetics,
pubmed-meshheading:2790007-Lasers,
pubmed-meshheading:2790007-Models, Theoretical,
pubmed-meshheading:2790007-Photochemistry,
pubmed-meshheading:2790007-Retinal Pigments,
pubmed-meshheading:2790007-Rhodopsin,
pubmed-meshheading:2790007-Rod Cell Outer Segment,
pubmed-meshheading:2790007-Spectrometry, Fluorescence,
pubmed-meshheading:2790007-Spectrophotometry,
pubmed-meshheading:2790007-Time Factors
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pubmed:year |
1989
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pubmed:articleTitle |
Mechanism of isomerization of rhodopsin studied by use of 11-cis-locked rhodopsin analogues excited with a picosecond laser pulse.
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pubmed:affiliation |
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
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pubmed:publicationType |
Journal Article,
Research Support, U.S. Gov't, P.H.S.,
Research Support, Non-U.S. Gov't
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