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Coupled HOOP signature correlates with quantum yield of isorhodopsin and analog pigments. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1858:118-125. [PMID: 27836700 DOI: 10.1016/j.bbabio.2016.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 09/29/2016] [Accepted: 11/04/2016] [Indexed: 11/21/2022]
Abstract
With a quantum yield of 0.66±0.03 the photoisomerization efficiency of the visual pigment rhodopsin (11-cis⇒all-trans chromophore) is exceptionally high. This is currently explained by coherent coupling of the excited state electronic wavepacket with local vibrational nuclear modes, facilitating efficient cross-over at a conical intersection onto the photoproduct energy surface. The 9-cis counterpart of rhodopsin, dubbed isorhodopsin, has a much lower quantum yield (0.26±0.03), which, however, can be markedly enhanced by modification of the retinal chromophore (7,8-dihydro and 9-cyclopropyl derivatives). The coherent coupling in the excited state is promoted by torsional skeletal and coupled HOOP vibrational modes, in combination with a twisted conformation around the isomerization region. Since such torsion will strongly enhance the infrared intensity of coupled HOOP modes, we investigated FTIR difference spectra of rhodopsin, isorhodopsin and several analog pigments in the spectral range of isolated and coupled HCCH wags. As a result we propose that the coupled HOOP signature in these retinal pigments correlates with the distribution of torsion over counteracting segments in the retinylidene polyene chain. As such the HOOP signature can act as an indicator for the photoisomerization efficiency, and can explain the higher quantum yield of the 7,8-dihydro and 9-cyclopropyl-isorhodopsin analogs.
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2
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Ockenfels A, Schapiro I, Gärtner W. Rhodopsins carrying modified chromophores--the 'making of', structural modelling and their light-induced reactivity. Photochem Photobiol Sci 2016; 15:297-308. [PMID: 26860474 DOI: 10.1039/c5pp00322a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
A series of vitamin-A aldehydes (retinals) with modified alkyl group substituents (9-demethyl-, 9-ethyl-, 9-isopropyl-, 10-methyl, 10-methyl-13-demethyl-, and 13-demethyl retinal) was synthesized and their 11-cis isomers were used as chromophores to reconstitute the visual pigment rhodopsin. Structural changes were selectively introduced around the photoisomerizing C11=C12 bond. The effect of these structural changes on rhodopsin formation and bleaching was determined. Global fit of assembly kinetics yielded lifetimes and spectral features of the assembly intermediates. Rhodopsin formation proceeds stepwise with prolonged lifetimes especially for 9-demethyl retinal (longest lifetime τ3 = 7500 s, cf., 3500 s for retinal), and for 10-methyl retinal (τ3 = 7850 s). These slowed-down processes are interpreted as either a loss of fixation (9dm) or an increased steric hindrance (10me) during the conformational adjustment within the protein. Combined quantum mechanics and molecular mechanics (QM/MM) simulations provided structural insight into the retinal analogues-assembled, full-length rhodopsins. Extinction coefficients, quantum yields and kinetics of the bleaching process (μs-to-ms time range) were determined. Global fit analysis yielded lifetimes and spectral features of bleaching intermediates, revealing remarkably altered kinetics: whereas the slowest process of wild-type rhodopsin and of bleached and 11-cis retinal assembled rhodopsin takes place with lifetimes of 7 and 3.8 s, respectively, this process for 10-methyl-13-demethyl retinal was nearly 10 h (34670 s), coming to completion only after ca. 50 h. The structural changes in retinal derivatives clearly identify the precise interactions between chromophore and protein during the light-induced changes that yield the outstanding efficiency of rhodopsin.
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Affiliation(s)
- Andreas Ockenfels
- Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim, Germany.
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Verhoeven MA, Bovee-Geurts PHM, de Groot HJM, Lugtenburg J, DeGrip WJ. Methyl Substituents at the 11 or 12 Position of Retinal Profoundly and Differentially Affect Photochemistry and Signalling Activity of Rhodopsin. J Mol Biol 2006; 363:98-113. [PMID: 16962138 DOI: 10.1016/j.jmb.2006.07.039] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 07/12/2006] [Accepted: 07/19/2006] [Indexed: 11/18/2022]
Abstract
The C-11=C-12 double bond of the retinylidene chromophore of rhodopsin holds a central position in its light-induced photoisomerization and hence the photosensory function of this visual pigment. To probe the local environment of the HC-11=C-12H element we have prepared the 11-methyl and 12-methyl derivatives of 11-Z retinal and incorporated these into opsin to generate the rhodopsin analogs 11-methyl and 12-methyl rhodopsin. These analog pigments form with much slower kinetics and lower efficiency than the native pigment. The initial photochemistry and the signaling activity of the analog pigments were investigated by UV-vis and FTIR spectroscopy, and by a G protein activation assay. Our data indicate that the ultrafast formation of the first photointermediate is strongly perturbed by the presence of an 11-methyl substituent, but much less by a 12-methyl substituent. These results support the current concept of the mechanism of the primary photoisomerization event in rhodopsin. An important stronghold of this concept is an out-of-plane movement of the C-12H element, which is facilitated by torsion as well as extended positive charge delocalization into the C-10-C-13 segment of the chromophore. We argue that this mechanism is maintained principally with a methyl substituent at C-12. In addition, we show that both an 11-methyl and a 12-methyl substitutent perturb the photointermediate cascade and finally yield a low-activity state of the receptor. The 11-methyl pigment retains about 30% of the G protein activation rate of native rhodopsin, while the 12-methyl chromophore behaves like an inverse agonist up to at least 20 degrees C, trapping the protein in a perturbed Meta-I-like conformation. We conclude that the isomerization region of the chromophore and the spatial structure of the binding site are finely tuned, in order to achieve a high photosensory potential with an efficient pathway to a high-activity state.
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4
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Melyan Z, Tarttelin EE, Bellingham J, Lucas RJ, Hankins MW. Addition of human melanopsin renders mammalian cells photoresponsive. Nature 2005; 433:741-5. [PMID: 15674244 DOI: 10.1038/nature03344] [Citation(s) in RCA: 273] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2004] [Accepted: 01/12/2005] [Indexed: 11/08/2022]
Abstract
A small number of mammalian retinal ganglion cells act as photoreceptors for regulating certain non-image forming photoresponses. These intrinsically photosensitive retinal ganglion cells express the putative photopigment melanopsin. Ablation of the melanopsin gene renders these cells insensitive to light; however, the precise role of melanopsin in supporting cellular photosensitivity is unconfirmed. Here we show that heterologous expression of human melanopsin in a mouse paraneuronal cell line (Neuro-2a) is sufficient to render these cells photoreceptive. Under such conditions, melanopsin acts as a sensory photopigment, coupled to a native ion channel via a G-protein signalling cascade, to drive physiological light detection. The melanopsin photoresponse relies on the presence of cis-isoforms of retinaldehyde and is selectively sensitive to short-wavelength light. We also present evidence to show that melanopsin functions as a bistable pigment in this system, having an intrinsic photoisomerase regeneration function that is chromatically shifted to longer wavelengths.
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Affiliation(s)
- Z Melyan
- Department of Visual Neuroscience, Division of Neuroscience and Psychological Medicine, Imperial College London, Charing Cross Hospital Campus, Fulham Palace Road, London W6 8RF, UK
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Verdegem PJ, Monnee MC, Lugtenburg J. Simple and efficient preparation of [10,20-13C2]- and [10-CH3,13-13C2]-10-methylretinal: introduction of substituents at the 2-position of 2,3-unsaturated nitriles. J Org Chem 2001; 66:1269-82. [PMID: 11312957 DOI: 10.1021/jo0009595] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In this paper, we present the synthesis of [10,20-13C2]-10-methylretinal and [10-CH3,13-13C2]-10-methylretinal, two doubly 13C-labeled chemically modified retinals that have been recently used to study the structural and functional details behind the photocascade of bovine rhodopsin (Verdegem et al. Biochemistry 1999, 38, 11316; de Lange et al. Biochemistry 1998, 37, 1411). To obtain both doubly 13C-labeled compounds, we developed a novel synthetic method to directly and regiospecifically introduce a methyl substituent on the 2-position of 3-methyl-5-(2',6',6'-trimethyl-1'-cyclohexen-1'-yl)-2,4-pentadienenitrile. Encouraged by these results, we investigated the scope of this novel reaction by developing a general method for the introduction of a variety of substituents to the 2-position of 3-methyl-2,3-unsaturated nitriles, paving the way for simple and efficient synthesis of a wide variety of 10-, 14-, and 10,14-substituted chemically modified retinals, and other biologically important compounds.
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Affiliation(s)
- P J Verdegem
- Leiden Institute of Chemistry, Leiden University, Gorlaeus Laboratoria, P.O. Box 9502, 2300 RA Leiden, The Netherlands
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6
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Iwasa T, Colmenares LU, Hirata K, Arime Y, Nakagawa M, Kikkawa S, Takashima H, Nosaka A, Naito A, Saitô H, Liu RSH, Tsuda M. 19F NMR and UV−Vis Absorption Spectroscopic Studies of Fluorinated Octopus Rhodopsin and Its Photoproducts. J Phys Chem A 1998. [DOI: 10.1021/jp9802477] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Tatsuo Iwasa
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Leticia U. Colmenares
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Kiyomi Hirata
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Yuko Arime
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Masashi Nakagawa
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Satoshi Kikkawa
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Hiroyuki Takashima
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Atsuko Nosaka
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Akira Naito
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Hazime Saitô
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Robert S. H. Liu
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
| | - Motoyuki Tsuda
- Department of Life Science, Faculty of Science, Himeji Institute of Technology, Kamigori, Ako-Gun, Hyogo 678-1297, Japan, Department of Chemistry, University of Hawaii, Honolulu, Hawaii 96822, and International Research Laboratories, Ciba-Geigy Japan Ltd., Takarazuka 665, Japan
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Francesch A, Alvarez R, López S, de Lera AR. Synthesis of Retinals Fluorinated at Odd-Numbered Side-Chain Positions and of the Corresponding Fluorobacteriorhodopsins. J Org Chem 1997; 62:310-319. [PMID: 11671404 DOI: 10.1021/jo961355x] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Conventional Horner-Wadsworth-Emmons and Wittig condensations were used to fluorinate the odd-numbered positions of the retinal side chain past C(7). The stereochemically labile cis-fluororetinals were easily converted into the most stable trans-fluororetinals, which were incubated with bacterio-opsin. Contrary to expectations, the fluorinated retinals provided artificial pigments with near normal absorption properties, showing that any electrostatic interactions between the fluorine atoms and protein groups were insufficient to prevent normal binding. The new artificial pigments had smaller opsin shifts than did native bacteriorhodopsin, which is interpreted as due either to greater electrostatic interaction between the protonated imine and its counterion, or to local interactions between the fluorine substituents and nearby polar protein groups.
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Affiliation(s)
- Andrés Francesch
- Departamento de Química Orgánica, Universidade de Santiago de Compostela, 15706 Santiago de Compostela, Spain
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9
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Koch D, Gärtner W. Steric hindrance between chromophore substituents as the driving force of rhodopsin photoisomerization: 10-methyl-13-demethyl retinal containing rhodopsin. Photochem Photobiol 1997; 65:181-6. [PMID: 9066300 DOI: 10.1111/j.1751-1097.1997.tb01896.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
A visual chromophore analogue, 10-methyl-13-demethyl (dm) retinal, was synthesized and reconstituted with bleached bovine rhodopsin to form a visual pigment derivative with absorbance maximum at 505 nm. The investigations with this new compound were stimulated from recent results using 13-dm retinal as a chromophore that revealed a remarkable loss in quantum efficiency (phi of 13-dm retinal-containing rhodopsin: 0.30, Ternieden and Gärtner, J. Photochem. Photobiol. B Biol, 33, 83-86, 1996). The quantum efficiency of the new pigment was determined as 0.59 by quantitative bleaching using reconstituted rhodopsin as a reference. The very similar quantum efficiencies of rhodopsin and the new pigment give experimental support for the recently presented hypothesis that a steric hindrance between the substituents at positions 10 and 13 in 11-cis-retinal is elevated during the photoisomerization and thus facilitates the rapid photoisomerization of the visual chromophore (Peteanu et al., Proc. Natl. Acad. Sci. USA 90, 11762-11766, 1993). Such steric hindrance is removed from the molecule by the elimination of the methyl group from position 13 and can be re-established via a rearrangement of the substitution pattern by introducing a methyl group at position 10 of 13-dm retinal.
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Affiliation(s)
- D Koch
- Max-Planck-Institut für Strahlenchemie, Mülheim an der Ruhr, Germany
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10
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Mirzadegan T, Humblet C, Ripka WC, Colmenares LU, Liu RS. Modeling rhodopsin, a member of G-protein coupled receptors, by computer graphics. Interpretation of chemical shifts of fluorinated rhodopsins. Photochem Photobiol 1992; 56:883-93. [PMID: 1492134 DOI: 10.1111/j.1751-1097.1992.tb09709.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An attempt has been made to construct a 3-D model of rhodopsin, a member of G-protein coupled receptors. Sequence homology of rhodopsin with the latter was a factor considered in the modeling procedure. The constructed model has been used to compare currently available specific protein/substrate interaction information, the shape of the binding cavity derived from shape of binding retinal isomers and analogs and challenged to explain recently available results from a series of fluorinated rhodopsins.
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Affiliation(s)
- T Mirzadegan
- Parke-Davis Pharmaceutical Research Division, Warner-Lambert Co., Ann Arbor, MI 48105
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11
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Gärtner W, Ullrich D, Vogt K. Quantum yield of CHAPSO-solubilized rhodopsin and 3-hydroxy retinal containing bovine opsin. Photochem Photobiol 1991; 54:1047-55. [PMID: 1837929 DOI: 10.1111/j.1751-1097.1991.tb02128.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The quantum yields of bleaching for two artificial pigments, bovine opsin combined with (3R)-3-hydroxy retinal or (3R,S)-3-methoxy retinal, were determined in comparison to the value for regenerated bovine rhodopsin. Regeneration of the visual pigments was performed by incubation of 3-[(3-Cholamidopropyl)-dimethylammonio]-2-hydroxy-1- propanesulfonate (CHAPSO)-solubilized opsin with the 11-cis isomers of retinal and the respective retinal derivatives. The extinction coefficients of the pigments in CHAPSO were determined to 35,000 M-1 cm-1 (native rhodopsin), 35,300 M-1 cm-1 (regenerated rhodopsin) and 34,500 M-1 cm-1 (3-OH retinal opsin). With respect to rhodopsin (lambda max: 500 nm), the pigments carrying the substituted chromophores exhibit blue shifted absorbance maxima (3-hydroxy and 3-methoxy retinal opsin: 488 nm). In parallel experiments under absolutely identical conditions we find related to the value of CHAPSO solubilized rhodopsin (identical to 1) a quantum efficiency of bleaching for the 3-hydroxy pigment of 1.2.
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Affiliation(s)
- W Gärtner
- Institut für Biologie I (Zoologie), Universität Freiburg, Fed. Rep. Germany
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12
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Colmenares LU, Asato AE, Denny M, Mead D, Zingoni JP, Liu RS. NMR studies of fluorinated visual pigment analogs. Biochem Biophys Res Commun 1991; 179:1337-43. [PMID: 1930178 DOI: 10.1016/0006-291x(91)91720-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The 19F-nmr chemical shift data of isomeric pigments (11-cis and 9-cis) of four vinyl fluororhodopsins and two trifluororhodopsins have been recorded. When compared with model protonated Schiff bases, a set of F-nmr opsin shift parameter (FOS) was obtained. The data revealed regiospecific protein perturbations on the F-resonances. They can be interpreted in terms of specific protein interactions such as the postulated second point charge and other polar interactions as well as the common hydrophobic protein perturbation.
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Affiliation(s)
- L U Colmenares
- Department of Chemistry, University of Hawaii, Honolulu 96822
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13
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Foster KW, Saranak J, Dowben PA. Spectral sensitivity, structure and activation of eukaryotic rhodopsins: activation spectroscopy of rhodopsin analogs in Chlamydomonas. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY. B, BIOLOGY 1991; 8:385-408. [PMID: 1828501 DOI: 10.1016/1011-1344(91)80114-w] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Retinal normally binds opsin forming the chromophore of the visual pigment, rhodopsin. In this investigation synthetic analogs were bound by the opsin of living cells of the alga Chlamydomonas reinhardtii; the effect was assayed by phototaxis to give an activation spectrum for each rhodopsin analog. The results show the influence of different chromophores and the protein on the absorption of light. The maxima of the phototaxis action spectra shifted systematically with the number of double bonds conjugated with the imine (C = N+H) bond of the chromophore. Chromophores lacking a beta-ionone ring, methyl groups and all C = C double bonds photoactivated the rhodopsin of Chlamydomonas with normal efficiency. On the basis of a simple model involving one-electron transitions between occupied and virtual molecular orbitals, we estimate the charge distribution along the chromophore in the binding site. With this restraint we define a unique structural model for eukaryotic rhodopsins and explain the spectral clustering of pigments, the spectral differences between red and green rhodopsins and the molecular basis of color blindness. Our results are consistent with the triggering of the activation of rhodopsin by the light-mediated change in electric dipole moment rather than the steric cis-trans isomerization of the chromophore.
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Affiliation(s)
- K W Foster
- Department of Physics, Syracuse University, NY 13244-1130
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14
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Yoshizawa T, Kandori H. Chapter 2 Primary photochemical events in the rhodopsin molecule. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0278-4327(91)90023-u] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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15
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Mirzadegan T, Liu RS. Chapter 3 Probing the visual pigment rhodopsin and its analogs by molecular modeling analysis and computer graphics. ACTA ACUST UNITED AC 1991. [DOI: 10.1016/0278-4327(91)90024-v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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16
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Affiliation(s)
- Y Shichida
- Department of Biophysics, Faculty of Science, Kyoto University, Japan
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17
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Asato AE, Zhang BW, Denny M, Mirzadegan T, Seff K, Liu RS. A study of the binding site requirements of rhodopsin using isomers of α-retinal and 5-substituted α-retinal analogs. Bioorg Chem 1989. [DOI: 10.1016/0045-2068(89)90042-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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18
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Kandori H, Shichida Y, Yoshizawa T. Absolute absorption spectra of batho- and photorhodopsins at room temperature. Picosecond laser photolysis of rhodopsin in polyacrylamide. Biophys J 1989; 56:453-7. [PMID: 2790133 PMCID: PMC1280498 DOI: 10.1016/s0006-3495(89)82692-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
Picosecond laser photolysis of rhodopsin in 15% polyacrylamide gel was performed for estimating absolute absorption spectra of the primary intermediates of cattle rhodopsin (bathorhodopsin and photorhodopsin). Using a rhodopsin digitonin extract embedded in 15% polyacrylamide gel, a precise percentage of bleaching of rhodopsin after excitation of a picosecond laser pulse was measured. Using this value, the absolute absorption spectrum of bathorhodopsin was calculated from the spectral change before and 1 ns after the picosecond laser excitation (corresponding to the difference spectrum between rhodopsin and bathorhodopsin). The absorption spectrum of bathorhodopsin thus obtained displayed a lambda max at 535 nm, which was shorter than that at low temperature (543 nm) and a half band-width broader than that measured at low temperature. The oscillator strength of bathorhodopsin at room temperature was smaller than that at low temperature. The absolute absorption spectrum of photorhodopsin was also estimated from the difference spectrum measured at 15 ps after the excitation of rhodopsin (Shichida, Y., S. Matuoka, and T. Yoshizawa. 1984. Photobiochem. Photobiophys. 7:221-228), assuming a sequential conversion of photorhodopsin to bathorhodopsin. Its lambda max was located at approximately 570 nm, and the oscillator strength was smaller than those of rhodopsin and bathorhodopsin.
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Affiliation(s)
- H Kandori
- Department of Biophysics, Faculty of Science, Kyoto University, Japan
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19
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Kandori H, Matuoka S, Nagai H, Shichida Y, Yoshizawa T. Dependency of apparent relative quantum yield of isorhodopsin to rhodopsin on the photon density of picosecond laser pulse. Photochem Photobiol 1988; 48:93-7. [PMID: 3217445 DOI: 10.1111/j.1751-1097.1988.tb02792.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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20
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Crescitelli F, Liu RS. The spectral properties and photosensitivities of analogue photopigments regenerated with 10- and 14-substituted retinal analogues. PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. SERIES B, BIOLOGICAL SCIENCES 1988; 233:55-76. [PMID: 2895933 DOI: 10.1098/rspb.1988.0012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Analogues of 11-cis- and 9-cis-retinal with substitutions at positions 10 and 14 were used to regenerate analogue photopigments with two opsins: that of the transmuted (cone-like) 521-pigment of Gekko gekko and that of the rhodopsin of Porichthys notatus. The spectral absorbances and photosensitivities of the regenerated photopigments were determined and compared, first, between the two systems of analogue photopigments, and second, in the responses to the two opsins. Unlike the 10-fluoropigments, the comparable 14-compounds were significantly red-shifted by 19-30 nm and their sensitivity to light was similar to that of the parent 11-cis- and 9-cis-pigments. These were the results for both analogue pigments. In contrast, the 10-pigments were spectrally located close to the wavelengths of the parent compounds and the photosensitivity was significantly reduced, especially in the case of the 9-cis-analogues. Evidence was obtained for a steric hindrance effect at position 14, for no regeneration was obtained when methyl or ethyl groups were at this carbon. In the 10-substituted retinals, steric hindrance was noted only for the gecko; only the fluorosubstituted, but not the chloro-, the methyl- or the ethyl-substituted, retinals reacted. With the fish opsin, pigments were regenerated with all but the ethyl-substituted retinal. The gecko opsin appears to have a more restricted binding site. Another feature of the gecko was related to the chloride bathochromic and hyperchromic effects, in which the 521-pigment prepared in a chloride-deficient state has a blue-shifted spectrum compared with the spectrum obtained after the addition of chloride, and its extinction is raised by the addition of chloride to give a mean ratio of 1.23 for the two extinctions, one with, the other without, added chloride. The 11-cis-10-F-analogue pigment gave both chloride effects and the hyperchromic ratio was the same as that recorded for the native visual pigment. In contrast, the pigment formed with 11-cis-14-F-retinal gave a hyperchromic ratio significantly greater than 1.23. A similar contrast in the responses to chloride was obtained with the analogue photopigments regenerated with the 9-cis-10-F- and 9-cis-14-F-chromophores. This difference between the two systems is interpreted as the result of a specific configurational feature of the gecko opsin when in the chloride-deficient state that is relevant to the binding of the retinal analogue.(ABSTRACT TRUNCATED AT 400 WORDS)
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Affiliation(s)
- F Crescitelli
- Department of Biology, University of California, Los Angeles 90024
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Abstract
This study confirms the occurrence of a dark-exchange reaction in the extracted 521-pigment of the Tokay gecko (G. gekko). The present study involved the exchange, in the dark, of the natural 11-cis-chromophore by the 9-cis-10-F-retinal analog. This analog is able to combine with the 521-opsin to regenerate a photopigment at 492 nm. In addition to this shift in absorbance from 521 to 492 nm, the analog photopigment has a photosensitivity some 2.4% that of the native 521-system in the chloride-sufficient state. These two properties of the regenerated analog pigment have simplified the demonstration of a dark exchange of chromophores. At 15 degrees C the 9-cis-10-F-analog replaces the 11-cis-chromophore by at least 30% (density-wise) in about 15 hr. This exchange occurs with the system in the chloride-deficient state. The presence of chloride during the period in the dark significantly reduces the magnitude of the exchange. Apparently, the protein has a more open structure at the chromophoric binding site, allowing this interchange of chromophores. The addition of chloride induces a conformational change at this site, 'burying' the Schiff base and reducing the exchange reaction. The biological implication of this mobile property of the gecko opsin is that it is similar to the behavior of the cone pigment iodopsin but is unlike that of rhodopsins. This supports the idea that the gecko visual cells, despite their appearance as rods, are phylogenetically related to ancestral photopic receptors.
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Affiliation(s)
- F Crescitelli
- Department of Biology, University of California, Los Angeles 90024
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