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Leeder AJ, Brown LJ, Becker-Baldus J, Mehler M, Glaubitz C, Brown RCD. Synthesis of isotopically labeled all-trans retinals for DNP-enhanced solid-state NMR studies of retinylidene proteins. J Labelled Comp Radiopharm 2018; 61:922-933. [PMID: 29080288 DOI: 10.1002/jlcr.3576] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2017] [Accepted: 10/17/2017] [Indexed: 12/28/2022]
Abstract
Three all-trans retinals containing multiple 13 C labels have been synthesized to enable dynamic nuclear polarization enhanced solid-state magic angle spinning NMR studies of novel microbial retinylidene membrane proteins including proteorhodpsin and channelrhodopsin. The synthetic approaches allowed specific introduction of 13 C labels in ring substituents and at different positions in the polyene chain to probe structural features such as ring orientation and interaction of the chromophore with the protein in the ground state and in photointermediates. [10-18-13 C9 ]-All-trans-retinal (1b), [12,15-13 C2 ]-all-trans-retinal (1c), and [14,15-13 C2 ]-all-trans-retinal (1d) were synthesized in in 12, 8, and 7 linear steps from ethyl 2-oxocyclohexanecarboxylate (5) or β-ionone (4), respectively.
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Affiliation(s)
| | - Lynda J Brown
- Department of Chemistry, University of Southampton, Southampton, UK
| | - Johanna Becker-Baldus
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany.,Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt, Germany
| | - Michaela Mehler
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany.,Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt, Germany
| | - Clemens Glaubitz
- Institute of Biophysical Chemistry, Goethe University Frankfurt, Frankfurt, Germany.,Centre for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Frankfurt, Germany
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2
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Masyuk VS, Mineeva IV. Synthesis of phenyl analog of retinoic acid methyl ester proceeding from 3-(bromomethyl)but-3-enal diethylacetal. RUSSIAN JOURNAL OF ORGANIC CHEMISTRY 2017. [DOI: 10.1134/s1070428017110045] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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3
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Mehler M, Scholz F, Ullrich SJ, Mao J, Braun M, Brown LJ, Brown RCD, Fiedler SA, Becker-Baldus J, Wachtveitl J, Glaubitz C. The EF loop in green proteorhodopsin affects conformation and photocycle dynamics. Biophys J 2014; 105:385-97. [PMID: 23870260 DOI: 10.1016/j.bpj.2013.06.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2013] [Revised: 06/10/2013] [Accepted: 06/11/2013] [Indexed: 11/20/2022] Open
Abstract
The proteorhodopsin family consists of retinal proteins of marine bacterial origin with optical properties adjusted to their local environments. For green proteorhodopsin, a highly specific mutation in the EF loop, A178R, has been found to cause a surprisingly large redshift of 20 nm despite its distance from the chromophore. Here, we analyze structural and functional consequences of this EF loop mutation by time-resolved optical spectroscopy and solid-state NMR. We found that the primary photoreaction and the formation of the K-like photo intermediate is almost pH-independent and slower compared to the wild-type, whereas the decay of the K-intermediate is accelerated, suggesting structural changes within the counterion complex upon mutation. The photocycle is significantly elongated mainly due to an enlarged lifetime of late photo intermediates. Multidimensional MAS-NMR reveals mutation-induced chemical shift changes propagating from the EF loop to the chromophore binding pocket, whereas dynamic nuclear polarization-enhanced (13)C-double quantum MAS-NMR has been used to probe directly the retinylidene conformation. Our data show a modified interaction network between chromophore, Schiff base, and counterion complex explaining the altered optical and kinetic properties. In particular, the mutation-induced distorted structure in the EF loop weakens interactions, which help reorienting helix F during the reprotonation step explaining the slower photocycle. These data lead to the conclusion that the EF loop plays an important role in proton uptake from the cytoplasm but our data also reveal a clear interaction pathway between the EF loop and retinal binding pocket, which might be an evolutionary conserved communication pathway in retinal proteins.
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Affiliation(s)
- Michaela Mehler
- Institute of Biophysical Chemistry and Centre for Biomolecular Magnetic Resonance, Goethe-University Frankfurt, Germany
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4
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Gebhard R, Courtin JML, Shadid JB, van Haveren J, van Haeringen CJ, Lugtenburg J. Synthesis of retinals labelled with 13C in the cyclohexene ring. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19891080602] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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5
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Gebhard R, van Dijk JTM, Boza MVTJ, van der Hoef K, Lugtenburg J. Synthesis and spectroscopic properties of 14-, 15-, 15′ - and 14′ -monodeutero- and 15,15′ -dideuterospheroidenes. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19911100706] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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6
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van der Steen R, Groesbeek M, van Amsterdam LJP, Lugtenburg J, van Oostrum J, de Grip WJ. All E-10,20-methanoretinoylopsin, light-stable rhodopsin. Synthesis and spectroscopy of all E-10,20-methano- and all-E-retinoyl fluoride and their reaction with bovine opsin. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19891080105] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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7
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Pardoen JA, van den Berg EMM, Winkel C, Lugtenburg J. Synthesis of retinals isotopically labelled at positions 11, 12, 14 and 20. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19861050304] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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8
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Courtin JML, Lam GK, Peters AJM, Lugtenburg J. Synthesis of 5-, 6-, 7- and 18-mono-13
C-labelled retinals. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19851041103] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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9
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Dawadi PBS, Lugtenburg J. Synthesis and use of stable isotope enriched retinals in the field of vitamin A. Molecules 2010; 15:1825-72. [PMID: 20336016 PMCID: PMC6257204 DOI: 10.3390/molecules15031825] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2010] [Revised: 02/18/2010] [Accepted: 03/02/2010] [Indexed: 01/05/2023] Open
Abstract
The role of vitamin A and its metabolites in the life processes starting with the historical background and its up to date information is discussed in the introduction. Also the role of 11Z-retinal in vision and retinoic acid in the biological processes is elucidated. The essential role of isotopically enriched systems in the progress of vision research, nutrition research etc. is discussed. In part B industrial commercial syntheses of vitamin A by the two leading companies Hoffmann-La Roche (now DSM) and BASF are discussed. The knowledge obtained via these pioneering syntheses has been essential for the further synthetic efforts in vitamin A field by other scientific groups. The rest of the paper is devoted to the synthetic efforts of the Leiden group that gives an access to the preparation of site directed high level isotope enrichment in retinals. First the synthesis of the retinals with deuterium incorporation in the conjugated side chain is reviewed. Then, 13C-labeled retinals are discussed. This is followed by the discussion of a convergent synthetic scheme that allows a rational access to prepare any isotopomer of retinals. The schemes that provide access to prepare any possible isotope enriched chemically modified systems are discussed. Finally, nor-retinals and bridged retinals that give access to a whole (as yet incomplete) library of possible isotopomers are reviewed.
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Affiliation(s)
- Prativa B S Dawadi
- Leiden Institute of Chemistry, Leiden University, P.O. Box 9502, 2300 RA, Leiden, The Netherlands.
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Hatcher ME, Hu JG, Belenky M, Verdegem P, Lugtenburg J, Griffin RG, Herzfeld J. Control of the pump cycle in bacteriorhodopsin: mechanisms elucidated by solid-state NMR of the D85N mutant. Biophys J 2002; 82:1017-29. [PMID: 11806941 PMCID: PMC1301908 DOI: 10.1016/s0006-3495(02)75461-1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
By varying the pH, the D85N mutant of bacteriorhodopsin provides models for several photocycle intermediates of the wild-type protein in which D85 is protonated. At pH 10.8, NMR spectra of [zeta-(15)N]lys-, [12-(13)C]retinal-, and [14,15-(13)C]retinal-labeled D85N samples indicate a deprotonated, 13-cis,15-anti chromophore. On the other hand, at neutral pH, the NMR spectra of D85N show a mixture of protonated Schiff base species similar to that seen in the wild-type protein at low pH, and more complex than the two-state mixture of 13-cis,15-syn, and all-trans isomers found in the dark-adapted wild-type protein. These results lead to several conclusions. First, the reversible titration of order in the D85N chromophore indicates that electrostatic interactions have a major influence on events in the active site. More specifically, whereas a straight chromophore is preferred when the Schiff base and residue 85 are oppositely charged, a bent chromophore is found when both the Schiff base and residue 85 are electrically neutral, even in the dark. Thus a "bent" binding pocket is formed without photoisomerization of the chromophore. On the other hand, when photoisomerization from the straight all-trans,15-anti configuration to the bent 13-cis,15-anti does occur, reciprocal thermodynamic linkage dictates that neutralization of the SB and D85 (by proton transfer from the former to the latter) will result. Second, the similarity between the chromophore chemical shifts in D85N at alkaline pH and those found previously in the M(n) intermediate of the wild-type protein indicate that the latter has a thoroughly relaxed chromophore like the subsequent N intermediate. By comparison, indications of L-like distortion are found for the chromophore of the M(o) state. Thus, chromophore strain is released in the M(o)-->M(n) transition, probably coincident with, and perhaps instrumental to, the change in the connectivity of the Schiff base from the extracellular side of the membrane to the cytoplasmic side. Because the nitrogen chemical shifts of the Schiff base indicate interaction with a hydrogen-bond donor in both M states, it is possible that a water molecule travels with the Schiff base as it switches connectivity. If so, the protein is acting as an inward-driven hydroxyl pump (analogous to halorhodopsin) rather than an outward-driven proton pump. Third, the presence of a significant C [double bond] N syn component in D85N at neutral pH suggests that rapid deprotonation of D85 is necessary at the end of the wild-type photocycle to avoid the generation of nonfunctional C [double bond] N syn species.
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Affiliation(s)
- Mary E Hatcher
- Department of Chemistry, Brandeis University, Waltham Massachusetts 02454, USA
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11
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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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McDermott AE, Creuzet F, Gebhard R, van der Hoef K, Levitt MH, Herzfeld J, Lugtenburg J, Griffin RG. Determination of internuclear distances and the orientation of functional groups by solid-state NMR: rotational resonance study of the conformation of retinal in bacteriorhodopsin. Biochemistry 1994; 33:6129-36. [PMID: 8193126 DOI: 10.1021/bi00186a012] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We have used a new solid-state NMR technique--rotational resonance--to determine both internuclear distances and the relative orientations of chemical groups (dihedral angles) in retinal bound to bacteriorhodopsin (bR) and in retinoic acid model compounds. By matching the rotational resonance condition (delta = n omega r/2 pi, where delta is the difference in isotropic chemical shifts for two dipolar coupled spins, omega r/2 pi is the mechanical rotational frequency of the sample in the MAS experiment, and n is a small integer denoting the order of the resonance), we selectively reintroduce the dipolar coupling and enhance the rate of magnetization exchange. Spectroscopic data and theoretical simulations of the magnetization exchange trajectories for the 8,18-13C dipolar coupled pair in retinoic acid model compounds, crystallized in both the 6-s-cis and 6-s-trans forms, indicate that an accurate determination of the internuclear distance is possible. For the n = 1 resonance we find the distance determination to be reasonably independent of the relative orientation of the groups. In contrast, for the n = 2 resonance, there is a more pronounced dependence on the relative orientation of the groups which permits an estimate of the angle around the 6-s bond for the cis and trans forms to be 42 +/- 5 degrees and 90 +/- 10 degrees, respectively, in good agreement with crystallography. In bR we demonstrate that the 8-13C-18-13C distance is 4.1 A and the average 8-13C-16-13C/8-13C-17-13C distance is 3.3-3.5 A.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- A E McDermott
- Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139
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13
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Sasaki J, Maeda A, Shichida Y, Groesbeek M, Lugtenburg J, Yoshizawa T. STRUCTURE OF HYPSORHODOPSIN: ANALYSIS BY FOURIER TRANSFORM INFRARED SPECTROSCOPY AT 10 K. Photochem Photobiol 1992. [DOI: 10.1111/j.1751-1097.1992.tb09730.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Fahmy K, Weidlich O, Engelhard M, Tittor J, Oesterhelt D, Siebert F. IDENTIFICATION OF THE PROTON ACCEPTOR OF SCHIFF BASE DEPROTONATION IN BACTERIORHODOPSIN: A FOURIER-TRANSFORM-INFRARED STUDY OF THE MUTANT ASP85 → GLU IN ITS NATURAL LIPID ENVIRONMENT. Photochem Photobiol 1992. [DOI: 10.1111/j.1751-1097.1992.tb09731.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Thompson LK, McDermott AE, Raap J, van der Wielen CM, Lugtenburg J, Herzfeld J, Griffin RG. Rotational resonance NMR study of the active site structure in bacteriorhodopsin: conformation of the Schiff base linkage. Biochemistry 1992; 31:7931-8. [PMID: 1510979 DOI: 10.1021/bi00149a026] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Rotational resonance, a new solid-state NMR technique for determining internuclear distances, is used to measure a distance in the active site of bacteriorhodopsin (bR) that changes in different states of the protein. The experiments are targeted to the active site of bR through 13C labeling of both the retinal chromophore and the Lys side chains of the protein. The time course of the rotor-driven magnetization exchange between a pair of 13C nuclei is then observed to determine the dipolar coupling and therefore the internuclear distance. Using this approach, we have measured the distance from [14-13C]retinal to [epsilon-13C]Lys216 in dark-adapted bR in order to examine the structure of the retinal-protein linkage and its role in coupling the isomerizations of retinal to unidirectional proton transfer. This distance depends on the configuration of the intervening C=N bond. The 3.0 +/- 0.2 A distance observed in bR555 demonstrates that the C=N bond is syn, and the 4.1 +/- 0.3 A distance observed in bR568 demonstrates that the C=N bond is anti. These direct distance determinations independently confirm the configurations previously deduced from solid-state NMR chemical shift and resonance Raman vibrational spectra. The spectral selectivity of rotational resonance allows these two distances to be measured independently in a sample containing both bR555 and bR568; the presence of both states and of 25% lipid in the sample demonstrates the use of rotational resonance to measure an active site distance in a membrane protein with an effective molecular mass of about 85 kDa.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- L K Thompson
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02139
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Smith SO, Palings I, Miley ME, Courtin J, de Groot H, Lugtenburg J, Mathies RA, Griffin RG. Solid-state NMR studies of the mechanism of the opsin shift in the visual pigment rhodopsin. Biochemistry 1990; 29:8158-64. [PMID: 2261469 DOI: 10.1021/bi00487a025] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Solid-state 13C NMR spectra have been obtained of bovine rhodopsin and isorhodopsin regenerated with retinal selectively 13C labeled along the polyene chain. In rhodopsin, the chemical shifts for 13C-5, 13C-6, 13C-7, 13C-14, and 13C-15 correspond closely to the chemical shifts observed in the 11-cis protonated Schiff base (PSB) model compound. Differences in chemical shift relative to the 11-cis PSB chloride salt are observed for positions 8 through 13, with the largest deshielding (6.2 ppm) localized at position 13. The localized deshielding at C-13 supports previous models of the opsin shift in rhodopsin that place a protein perturbation in the vicinity of position 13. Spectra obtained of isorhodopsin regenerated with 13C-labeled 9-cis-retinals reveal large perturbations at 13C-7 and 13C-13. The similar deshielding of the 13C-13 resonance in both pigments supports the presence of a protein perturbation near position 13. However, the chemical shifts at positions 7 and 12 in isorhodopsin are not analogous to those observed in rhodopsin and suggest that the binding site interactions near these positions are different for the two pigments. The implications of these results for the mechanism of the opsin shift in these proteins are discussed.
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Affiliation(s)
- S O Smith
- Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139
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de Groot HJ, Smith SO, Courtin J, van den Berg E, Winkel C, Lugtenburg J, Griffin RG, Herzfeld J. Solid-state 13C and 15N NMR study of the low pH forms of bacteriorhodopsin. Biochemistry 1990; 29:6873-83. [PMID: 2168744 DOI: 10.1021/bi00481a017] [Citation(s) in RCA: 109] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The visible absorption of bacteriorhodopsin (bR) is highly sensitive to pH, the maximum shifting from 568 nm (pH 7) to approximately 600 nm (pH 2) and back to 565 nm (pH 0) as the pH is decreased further with HCl. Blue membrane (lambda max greater than 600 nm) is also formed by deionization of neutral purple membrane suspensions. Low-temperature, magic angle spinning 13C and 15N NMR was used to investigate the transitions to the blue and acid purple states. The 15N NMR studies involved [epsilon-15N]lysine bR, allowing a detailed investigation of effects at the Schiff base nitrogen. The 15N resonance shifts approximately 16 ppm upfield in the neutral purple to blue transition and returns to its original value in the blue to acid purple transition. Thus, the 15N shift correlates directly with the color changes, suggesting an important contribution of the Schiff base counterion to the "opsin shift". The results indicate weaker hydrogen bonding in the blue form than in the two purple forms and permit a determination of the contribution of the weak hydrogen bonding to the opsin shift at a neutral pH of approximately 2000 cm-1. An explanation of the mechanism of the purple to blue to purple transition is given in terms of the complex counterion model. The 13C NMR experiments were performed on samples specifically 13C labeled at the C-5, C-12, C-13, C-14, or C-15 positions in the retinylidene chromophore. The effects of the purple to blue to purple transitions on the isotropic chemical shifts for the various 13C resonances are relatively small. It appears that bR600 consists of at least four different species. The data confirm the presence of 13-cis- and all-trans-retinal in the blue form, as in neutral purple dark-adapted bR. All spectra of the blue and acid purple bR show substantial inhomogeneous broadening which indicates additional irregular distortions of the protein lattice. The amount of distortion correlates with the variation of the pH, and not with the color change.
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Affiliation(s)
- H J de Groot
- Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139
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Fahmy K, Siebert F. THE PHOTOREACTION OF THE DEIONIZED FORM OF THE PURPLE MEMBRANE INVESTIGATED BY FTIR DIFFERENCE SPECTROSCOPY. Photochem Photobiol 1990. [DOI: 10.1111/j.1751-1097.1990.tb01737.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Fahmy K, Siebert F, Großjean M, Tavan P. Photoisomerization in bacteriorhodopsin studied by FTIR, linear dichroism and photoselection experiments combined with quantum chemical theoretical analysis. J Mol Struct 1989. [DOI: 10.1016/0022-2860(89)80017-1] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Smith SO, de Groot HJ, Gebhard R, Courtin JM, Lugtenburg J, Herzfeld J, Griffin RG. Structure and protein environment of the retinal chromophore in light- and dark-adapted bacteriorhodopsin studied by solid-state NMR. Biochemistry 1989; 28:8897-904. [PMID: 2605231 DOI: 10.1021/bi00448a032] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Our previous solid-state 13C NMR studies on bR have been directed at characterizing the structure and protein environment of the retinal chromophore in bR568 and bR548, the two components of the dark-adapted protein. In this paper, we extend these studies by presenting solid-state NMR spectra of light-adapted bR (bR568) and examining in more detail the chemical shift anisotropy of the retinal resonances near the ionone ring and Schiff base. Magic angle spinning (MAS) 13C NMR spectra were obtained of bR568, regenerated with retinal specifically 13C labeled at positions 12-15, which allowed assignment of the resonances observed in the dark-adapted bR spectrum. Of particular interest are the assignments of the 13C-13 and 13C-15 resonances. The 13C-15 chemical resonance for bR568 (160.0 ppm) is upfield of the 13C-15 resonance for bR548 (163.3 ppm). This difference is attributed to a weaker interaction between the Schiff base and its associated counterion in bR568. The 13C-13 chemical shift for bR568 (164.8 ppm) is close to that of the all-trans-retinal protonated Schiff base (PSB) model compound (approximately 162 ppm), while the 13C-13 resonance for bR548 (168.7 ppm) is approximately 7 ppm downfield of that of the 13-cis PSB model compound. The difference in the 13C-13 chemical shift between bR568 and bR548 is opposite that expected from the corresponding 15N chemical shifts of the Schiff base nitrogen and may be due to conformational distortion of the chromophore in the C13 = C14-C15 bonds.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- S O Smith
- Francis Bitter National Magnet Laboratory, Massachusetts Institute of Technology, Cambridge 02139
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Palings I, van den Berg EM, Lugtenburg J, Mathies RA. Complete assignment of the hydrogen out-of-plane wagging vibrations of bathorhodopsin: chromophore structure and energy storage in the primary photoproduct of vision. Biochemistry 1989; 28:1498-507. [PMID: 2719913 DOI: 10.1021/bi00430a012] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Resonance Raman vibrational spectra of the retinal chromophore in bathorhodopsin have been obtained after regenerating bovine visual pigments with an extensive series of 13C- and deuterium-labeled retinals. A low-temperature spinning cell technique was used to produce high-quality bathorhodopsin spectra exhibiting resolved hydrogen out-of-plane wagging vibrations at 838, 850, 858, 875, and 921 cm-1. The isotopic shifts and a normal coordinate analysis permit the assignment of these lines to the HC7 = C8H Bg, C14H, C12H, C10H, and C11H hydrogen out-of-plane wagging modes, respectively. The coupling constant between the C11H and C12H wags as well as the C12H wag force constant are unusually low compared to those of retinal model compounds. This quantitatively confirms the lack of coupling between the C11H and C12H wags and the low C12H wag vibrational frequency noted earlier by Eyring et al. [(1982) Biochemistry 21, 384]. The force constants for the C10H and C14H wags are also significantly below the values observed in model compounds. We suggest that the perturbed hydrogen out-of-plane wagging and C-C stretching force constants for the C10-C11 = C12-C13 region of the chromophore in bathorhodopsin result from electrostatic interactions with a charged protein residue. This interaction may also contribute to the 33 kcal/mol energy storage in bathorhodopsin.
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Affiliation(s)
- I Palings
- Department of Chemistry, University of California, Berkeley 94720
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Roepe PD, Ahl PL, Herzfeld J, Lugtenburg J, Rothschild KJ. Tyrosine protonation changes in bacteriorhodopsin. A Fourier transform infrared study of BR548 and its primary photoproduct. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)60686-6] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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