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Abstract
Duchenne muscular dystrophy is a severe, progressive, muscle-wasting disease that leads to difficulties with movement and, eventually, to the need for assisted ventilation and premature death. The disease is caused by mutations in DMD (encoding dystrophin) that abolish the production of dystrophin in muscle. Muscles without dystrophin are more sensitive to damage, resulting in progressive loss of muscle tissue and function, in addition to cardiomyopathy. Recent studies have greatly deepened our understanding of the primary and secondary pathogenetic mechanisms. Guidelines for the multidisciplinary care for Duchenne muscular dystrophy that address obtaining a genetic diagnosis and managing the various aspects of the disease have been established. In addition, a number of therapies that aim to restore the missing dystrophin protein or address secondary pathology have received regulatory approval and many others are in clinical development.
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Affiliation(s)
- Dongsheng Duan
- Department of Molecular Microbiology and Immunology and Department of Neurology, School of Medicine; Department of Biomedical Sciences, College of Veterinary Medicine; Department of Biomedical, Biological & Chemical Engineering, College of Engineering, University of Missouri, Columbia, MO, USA
| | - Nathalie Goemans
- Department of Child Neurology, University Hospitals Leuven, Leuven, Belgium
| | | | - Eugenio Mercuri
- Centro Clinico Nemo, Policlinico Gemelli, Rome, Italy
- Peadiatric Neurology, Catholic University, Rome, Italy
| | - Annemieke Aartsma-Rus
- Department of Human Genetics, Leiden University Medical Center, Leiden, The Netherlands.
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2
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Kliger DS, Lewis JW. Spectral and Kinetic Characterization of Visual Pigment Photointermediates. Isr J Chem 2013. [DOI: 10.1002/ijch.199500032] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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3
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Chung WC, Nanbu S, Ishida T. QM/MM Trajectory Surface Hopping Approach to Photoisomerization of Rhodopsin and Isorhodopsin: The Origin of Faster and More Efficient Isomerization for Rhodopsin. J Phys Chem B 2012; 116:8009-23. [DOI: 10.1021/jp212378u] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wilfredo Credo Chung
- Fukui Institute
for Fundamental Chemistry, Kyoto University, 34-4, Takano-nishihirakicho, Sakyo-ku, Kyoto 606-8103, Japan
| | - Shinkoh Nanbu
- Department of Materials
and Life Sciences, Faculty of Science and Engineering, Sophia University, Kioicho, Chiyoda-ku, Tokyo 102-8554,
Japan
| | - Toshimasa Ishida
- Fukui Institute
for Fundamental Chemistry, Kyoto University, 34-4, Takano-nishihirakicho, Sakyo-ku, Kyoto 606-8103, Japan
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4
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Kaila VRI, Send R, Sundholm D. The effect of protein environment on photoexcitation properties of retinal. J Phys Chem B 2012; 116:2249-58. [PMID: 22166007 DOI: 10.1021/jp205918m] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Retinal is the photon absorbing chromophore of rhodopsin and other visual pigments, enabling the vertebrate vision process. The effects of the protein environment on the primary photoexcitation process of retinal were studied by time-dependent density functional theory (TDDFT) and the algebraic diagrammatic construction through second order (ADC(2)) combined with our recently introduced reduction of virtual space (RVS) approximation method. The calculations were performed on large full quantum chemical cluster models of the bluecone (BC) and rhodopsin (Rh) pigments with 165-171 atoms. Absorption wavelengths of 441 and 491 nm were obtained at the B3LYP level of theory for the respective models, which agree well with the experimental values of 414 and 498 nm. Electrostatic rather than structural strain effects were shown to dominate the spectral tuning properties of the surrounding protein. The Schiff base retinal and a neighboring Glu-113 residue were found to have comparable proton affinities in the ground state of the BC model, whereas in the excited state, the proton affinity of the Schiff base is 5.9 kcal/mol (0.26 eV) higher. For the ground and excited states of the Rh model, the proton affinity of the Schiff base is 3.2 kcal/mol (0.14 eV) and 7.9 kcal/mol (0.34 eV) higher than for Glu-113, respectively. The protein environment was found to enhance the bond length alternation (BLA) of the retinyl chain and blueshift the first absorption maxima of the protonated Schiff base in the BC and Rh models relative to the chromophore in the gas phase. The protein environment was also found to decrease the intensity of the second excited state, thus improving the quantum yield of the photoexcitation process. Relaxation of the BC model on the excited state potential energy surface led to a vanishing BLA around the isomerization center of the conjugated retinyl chain, rendering the retinal accessible for cis-trans isomerization. The energy of the relaxed excited state was found to be 30 kcal/mol (1.3 eV) above the minimum ground state energy, and might be related to the transition state of the thermal activation process.
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Affiliation(s)
- Ville R I Kaila
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892, USA.
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5
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Send R, Sundholm D, Johansson MP, Pawłowski F. Excited State Potential Energy Surfaces of Polyenes and Protonated Schiff Bases. J Chem Theory Comput 2009; 5:2401-14. [DOI: 10.1021/ct900240s] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Robert Send
- Institut für Physikalische Chemie, Universität Karlsruhe, Kaiserstrasse 12, D-76128 Karlsruhe, Germany
| | - Dage Sundholm
- Department of Chemistry, P.O. Box 55 (A.I. Virtanens plats 1), University of Helsinki, FI-00014 Helsinki, Finland
| | - Mikael P. Johansson
- Lundbeck Foundation Centre for Theoretical Chemistry, Aarhus University, Langelandsgade 140, DK-8000 Århus C, Denmark
| | - Filip Pawłowski
- Physics Institute, Kazimierz Wielki University, Plac Weyssenhoffa 11, PL-85-072 Bydgoszcz, Poland
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6
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Concistrè M, Gansmüller A, McLean N, Johannessen OG, Marín Montesinos I, Bovee-Geurts PHM, Brown RCD, DeGrip WJ, Levitt MH. Light penetration and photoisomerization in rhodopsin studied by numerical simulations and double-quantum solid-state NMR spectroscopy. J Am Chem Soc 2009; 131:6133-40. [PMID: 19354207 DOI: 10.1021/ja809878c] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The penetration of light into optically thick samples containing the G-protein-coupled receptor rhodopsin is studied by numerical finite-element simulations and double-quantum solid-state NMR experiments. Illumination with white light leads to the generation of the active bathorhodopsin photostate in the outer layer of the sample but generates a large amount of the side product, isorhodopsin, in the sample interior. The overall yield of bathorhodopsin is improved by using monochromatic 420 nm illumination and by mixing the sample with transparent glass beads. The implications of these findings on the interpretation of previously published rhodopsin NMR data are discussed.
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Matsumoto H, Yoshizawa T. Rhodopsin Regeneration is AcceleratedviaNoncovalent 11-cisRetinalOpsin ComplexA Role of Retinal Binding Pocket of Opsin. Photochem Photobiol 2008; 84:985-9. [DOI: 10.1111/j.1751-1097.2008.00338.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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8
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The molecular structure of a curl-shaped retinal isomer. J Mol Model 2008; 14:717-26. [DOI: 10.1007/s00894-008-0284-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2007] [Accepted: 02/05/2008] [Indexed: 10/22/2022]
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Fel'dman TB, Fedorovich IB, Ostrovskii MA. Characteristics of the photoconversion of rhodopsin in the early stages of photolysis. ACTA ACUST UNITED AC 2004; 34:735-42. [PMID: 15526430 DOI: 10.1023/b:neab.0000036015.85880.9b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Low-temperature spectrophotometry was used to study the primary stages of rhodopsin photolysis. A digitonin extract of rhodopsin was irradiated at -155 degrees C with blue light of wavelength 436 nm. The stage of the bathorhodopsin --> lumirhodopsin conversion was accompanied by the simultaneous formation of several products. Formation of an intermediate product spectrally similar to the known "blue-shifted intermediate" (BSI) was demonstrated. It is suggested that the appearance of more than one intermediate product at each stage of photolysis reflects the existence of several conformational states of the rhodopsin molecule during its photoconversion.
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Affiliation(s)
- T B Fel'dman
- Institute of Biochemical Physics, Russian Academy of Sciences, 4 Kosygin Street, 119991 Moscow, Russia
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10
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Niu SL, Mitchell DC, Litman BJ. Manipulation of cholesterol levels in rod disk membranes by methyl-beta-cyclodextrin: effects on receptor activation. J Biol Chem 2002; 277:20139-45. [PMID: 11889130 DOI: 10.1074/jbc.m200594200] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The effect of cholesterol on rod outer segment disk membrane structure and rhodopsin activation was investigated. Disk membranes with varying cholesterol concentrations were prepared using methyl-beta-cyclodextrin as a cholesterol donor or acceptor. Cholesterol exchange followed a simple equilibrium partitioning model with a partition coefficient of 5.2 +/- 0.8 in favor of the disk membrane. Reduced cholesterol in disk membranes resulted in a higher proportion of photolyzed rhodopsin being converted to the G protein-activating metarhodopsin II (MII) conformation, whereas enrichment of cholesterol reduced the extent of MII formation. Time-resolved fluorescence anisotropy measurements using 1,6-diphenyl-1,3,5-hexatriene showed that increasing cholesterol reduced membrane acyl chain packing free volume as characterized by the parameter f(v). The level of MII formed showed a positive linear correlation with f(v) over the range of 4 to 38 mol % cholesterol. In addition, the thermal stability of rhodopsin increased with mol % of cholesterol in disk membranes. No evidence was observed for the direct interaction of cholesterol with rhodopsin in either its agonist- or antagonist-bound form. These results indicate that cholesterol mediates the function of the G protein-coupled receptor, rhodopsin, by influencing membrane lipid properties, i.e. reducing acyl chain packing free volume, rather than interacting specifically with rhodopsin.
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Affiliation(s)
- Shui-Lin Niu
- Section of Fluorescence Studies, Laboratory of Membrane Biochemistry and Biophysics, National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland 20852
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11
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McBee JK, Palczewski K, Baehr W, Pepperberg DR. Confronting complexity: the interlink of phototransduction and retinoid metabolism in the vertebrate retina. Prog Retin Eye Res 2001; 20:469-529. [PMID: 11390257 DOI: 10.1016/s1350-9462(01)00002-7] [Citation(s) in RCA: 259] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Absorption of light by rhodopsin or cone pigments in photoreceptors triggers photoisomerization of their universal chromophore, 11-cis-retinal, to all-trans-retinal. This photoreaction is the initial step in phototransduction that ultimately leads to the sensation of vision. Currently, a great deal of effort is directed toward elucidating mechanisms that return photoreceptors to the dark-adapted state, and processes that restore rhodopsin and counterbalance the bleaching of rhodopsin. Most notably, enzymatic isomerization of all-trans-retinal to 11-cis-retinal, called the visual cycle (or more properly the retinoid cycle), is required for regeneration of these visual pigments. Regeneration begins in rods and cones when all-trans-retinal is reduced to all-trans-retinol. The process continues in adjacent retinal pigment epithelial cells (RPE), where a complex set of reactions converts all-trans-retinol to 11-cis-retinal. Although remarkable progress has been made over the past decade in understanding the phototransduction cascade, our understanding of the retinoid cycle remains rudimentary. The aim of this review is to summarize recent developments in our current understanding of the retinoid cycle at the molecular level, and to examine the relevance of these reactions to phototransduction.
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Affiliation(s)
- J K McBee
- Department of Ophthalmology, University of Washington, Seattle, WA 98195, USA
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12
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Degrip W, Rothschild K. Chapter 1 Structure and mechanism of vertebrate visual pigments. ACTA ACUST UNITED AC 2000. [DOI: 10.1016/s1383-8121(00)80004-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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13
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Müller A, Lochbrunner S, Schmid W, Fuß W. Tieftemperaturphotochemie von Prävitamin D: Hula-Twist-Isomerisierung eines Triens. Angew Chem Int Ed Engl 1998. [DOI: 10.1002/(sici)1521-3757(19980216)110:4<520::aid-ange520>3.0.co;2-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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Mah TL, Lewis JW, Sheves M, Ottolenghi M, Kliger DS. Low-temperature trapping of early photointermediates of alpha-isorhodopsin. Photochem Photobiol 1995; 62:356-60. [PMID: 7480145 DOI: 10.1111/j.1751-1097.1995.tb05282.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Alpha-Isorhodopsin, an artificial visual pigment with a 9-cis-4,5-dehydro-5,6-dihydro(alpha)retinal chromophore, was photolyzed at low temperatures and absorption difference spectra were collected as the sample was warmed. A bathorhodopsin (Batho)-like intermediate absorbing at ca 495 nm was detected below 55 K,a blue-shifted intermediate (BSI)-like intermediate absorbing at ca 453 nm was observed when the temperature was raised to 60 K and a lumirhodopsin (Lumi)-like intermediate absorbing at ca 470 nm was found when the sample was warmed to 115 K. Photointermediates from this pigment were compared to those of native rhodopsin and 5,6-dihydroisorhodopsin. As in native rhodopsin, Batho is the first intermediate detected in alpha-isorhodopsin, though unlike native rhodopsin at low temperatures BSI is observed prior to Lumi formation. Alpha-Isohodopsin behaves similarly to 5,6-dihydroisorhodopsin, with the same early intermediates observed in both artificial visual pigments lacking the C5-C6 double bond. The transition temperature for BSI formation is higher in alpha-isorhodopsin, suggesting an interaction involving the chromophore ring in BSI formation. The transition temperature for Lumi formation is similar for these two pigments as well as for native rhodopsin, suggesting comparable changes in the protein environment in that transition.
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Affiliation(s)
- T L Mah
- Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064, USA
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15
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Abstract
Much progress has been made in recent years toward understanding the interactions between various proteins responsible for visual transduction which are initiated by an activated state of visual pigments. However, the changes which take place in the visual pigments themselves to convert them to the activated state are more poorly understood. Many spectroscopic techniques have been applied to this problem in recent years and considerable progress has been made. A major goal of these efforts is to understand at which stages protein change occurs and to characterize its structural features. In the visual system evidence is accumulating, for example, that chromophore independent protein change begins immediately prior to lumirhodopsin formation. Considerable insight has been gained recently into the early intermediates of visual transduction and the stage is set to achieve similar understanding of the later intermediates leading to rhodopsin's activated state.
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Affiliation(s)
- J W Lewis
- Department of Chemistry and Biochemistry, University of California, Santa Cruz 95064
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16
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Abstract
The vertebrate retina contains two kinds of visual cells: rods, responsible for twilight (scotopic) vision (black and white discrimination); and cones, responsible for daylight (photopic) vision (color discrimination). Here we attempt to explain some of their functional differences and similarities in terms of their visual pigments. In the chicken retina there are four types of single cones and a double cone; each of the single cones has its own characteristic oil droplet (red, orange, blue, or colorless) and the double cone is composed of a set of principal and accessory members, the former of which has a green-colored oil droplet. Iodopsin, the chicken red-sensitive cone visual pigment, is located at outer segments of both the red single cones and the double cones, while the other single cones and the rod contain their own visual pigments with different absorption spectra. The diversity in absorption spectra among these visual pigments is caused by the difference in interaction between chromophore (11-cis retinal) and protein moiety (opsin). However, the chromophore-binding pocket in iodopsin is similar to that in rhodopsin. The difference in absorption maxima between both pigments could be explained by the difference in distances between the protonated Schiff-bases at the chromophore-binding site and their counter ions in iodopsin and rhodopsin. Furthermore, iodopsin has a unique chloride-binding site whose chloride ion serves for the red-shift of the absorption maximum of iodopsin. Visual pigment bleaches upon absorption of light through several intermediates and finally dissociates into all-trans retinal and opsin. That the sensitivity of cones is lower than rods cannot be explained by the relative photosensitivity of iodopsin to rhodopsin, but may be understood to some extent by the short lifetime of an enzymatically active intermediate (corresponding to metarhodopsin II) produced in the photobleaching process of iodopsin. The rapid formation and decay of the meta II-intermediate of iodopsin compared with metarhodopsin II are not contradictory to the rapid generation and recovery of cone receptor potential compared with rod receptor potential. The rapid recovery of the cone receptor potential may be due to a more effective shutoff mechanism of the visual excitation, including the phosphorylation of iodopsin. The rapid dark adaptation of cones compared with rods has been explained by the rapid regeneration of iodopsin from 11-cis retinal and opsin. One of the reasons for the rapid regeneration and susceptibility to chemicals of iodopsin compared with rhodopsin may be a unique structure near the chromophore-binding site of iodopsin.
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Affiliation(s)
- T Yoshizawa
- Department of Applied Physics and Chemistry, University of Electro-Communications, Tokyo, Japan
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Birge RR. Nature of the primary photochemical events in rhodopsin and bacteriorhodopsin. BIOCHIMICA ET BIOPHYSICA ACTA 1990; 1016:293-327. [PMID: 2184895 DOI: 10.1016/0005-2728(90)90163-x] [Citation(s) in RCA: 302] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- R R Birge
- Department of Chemistry, Syracuse University, NY 13244
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Ottolenghi M, Sheves M. Synthetic retinals as probes for the binding site and photoreactions in rhodopsins. J Membr Biol 1989; 112:193-212. [PMID: 2693733 DOI: 10.1007/bf01870951] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Affiliation(s)
- M Ottolenghi
- Department of Physical Chemistry, Hebrew University of Jerusalem, Israel
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Albeck A, Friedman N, Ottolenghi M, Sheves M, Einterz CM, Hug SJ, Lewis JW, Kliger DS. Photolysis intermediates of the artificial visual pigment cis-5,6-dihydro-isorhodopsin. Biophys J 1989; 55:233-41. [PMID: 2713437 PMCID: PMC1330464 DOI: 10.1016/s0006-3495(89)82798-5] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The photolysis intermediates of an artificial bovine rhodopsin pigment, cis-5,6-dihydro-isorhodopsin (cis-5,6,-diH-ISORHO, lambda max 461 nm), which contains a cis-5,6-dihydro-9-cis-retinal chromophore, are investigated by room temperature, nanosecond laser photolysis, and low temperature irradiation studies. The observations are discussed both in terms of low temperature experiments of Yoshizawa and co-workers on trans-5,6-diH-ISORHO (Yoshizawa, T., Y. Shichida, and S. Matuoka. 1984. Vision Res. 24: 1455-1463), and in relation to the photolysis intermediates of native bovine rhodopsin (RHO). It is suggested that in 5,6-diH-ISORHO, a primary bathorhodopsin intermediate analogous to the bathorhodopsin intermediate (BATHO) of the native pigment, rapidly converts to a blue-shifted intermediate (BSI, lambda max 430 nm) which is not observed after photolysis of native rhodopsin. The analogs from lumirhodopsin (LUMI) to meta-II rhodopsin (META-II) are generated subsequent to BSI, similar to their generation from BATHO in the native pigment. It is proposed that the retinal chromophore in the bathorhodopsin stage of 5,6-diH-ISORHO is relieved of strain induced by the primary cis to trans isomerization by undergoing a geometrical rearrangement of the retinal. Such a rearrangement, which leads to BSI, would not take place so rapidly in the native pigment due to ring-protein interactions. In the native pigment, the strain in BATHO would be relieved only on a longer time scale, via a process with a rate determined by protein relaxation.
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Affiliation(s)
- A Albeck
- Department of Organic Chemistry, Weizmann Institute of Science, Rehovot, Israel
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