A second crystal form of 11‐<i>cis</i>, 12‐<i>cis</i> retinal, the chromophoric group in visual pigments

Drikos, G.; Rüppel, H.; Dietrich, Hans; Sperling, W.

doi:10.1016/0014-5793(81)80878-2

Cited by 17 publications

(7 citation statements)

References 24 publications

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“…The normal modes were computed for the energy-minimized 11-cis PSB structure (Figure 2). Its ground-state C 6 -C 7 dihedral angle is twisted by ∼36°to minimize nonbonded interaction between the 5-methyl group and the C 8 hydrogen, consistent with the ∼41°angle determined from X-ray 59,60 and NMR 61 structures of 11-cis retinal. The steric hindrance between the 10H and 13-methyl groups in the 12-s-trans conformer is likewise accommodated by a groundstate torsion of ∼22°about the C 12 -C 13 bond.…”

Section: Resultssupporting

confidence: 79%

“…Furthermore, 11- cis retinal crystal displays a unique band at 193 cm -1 that is not present in our solution spectrum. This band may be characteristic of the 12-s- cis species because the 11- cis retinal is known to crystallize in this conformation. , …”

Section: Resultsmentioning

confidence: 99%

“…This band may be characteristic of the 12s-cis species because the 11-cis retinal is known to crystallize in this conformation. 59,60 Rhodopsin and Isorhodopsin Preresonance Spectra. The Raman spectra of rhodopsin and isorhodopsin obtained with 792-nm excitation are shown in Figure 10.…”

Section: Resultsmentioning

confidence: 99%

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Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C₁₁C₁₂ Torsion Coordinate

et al. 1998

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The resonance Raman spectrum of the 11-cis retinal protonated Schiff base chromophore in rhodopsin exhibits low-frequency normal modes at 93, 131, 246, 260, 320, 446, and 568 cm -1 . Their relatively strong Raman activities reveal that the photoexcited chromophore undergoes rapid nuclear motion along torsional coordinates that may be involved in the 200-fs isomerization about the C 11 dC 12 bond. Resonance Raman spectra of rhodopsins regenerated with isotopically labeled retinal derivatives and demethyl retinal analogues were obtained in order to determine the vibrational character of these low-frequency modes and to assign the C 11 dC 12 torsional mode. 13 C substitutions of atoms in the C 12 -C 13 or C 13 dC 14 bond cause the 568-cm -1 mode to shift by ∼8 cm -1 , and deuteration of the C 11 dC 12 bond downshifts the 568-and 260-cm -1 modes by ∼35 and 5 cm -1 , respectively. The magnitudes of these shifts are consistent with those calculated for modes containing significant C 11 dC 12 torsional character. Thus, we assign the 568-cm -1 mode to a localized C 11 dC 12 torsion and the 260-cm -1 mode to a more delocalized torsional vibration involving coordinates from C 10 to C 13 . Consistent with these assignments, these two modes are not Raman active in 13-demethyl, 11-cis rhodopsin which has a planar C 10 ‚‚‚C 13 geometry. Furthermore, the relative Raman scattering strengths of the 260-and 568-cm -1 modes are ∼2-fold higher with preresonant excitation. These data quantitate the instantaneous torsional dynamics of the chromophore about its C 11 dC 12 bond on the S 1 surface and indicate that the isomerization process is facilitated by vibronic coupling of the S 1 and S 2 surfaces via C 11 dC 12 torsional distortion, which reduces the excited-state barrier along the reaction trajectory. We have also examined the low-frequency Raman spectrum of the trans primary photoproduct, bathorhodopsin, and discuss the relevance of its low-frequency torsional modes at ∼54, 92, 128, 151, 262, 276, 324, and 376 cm -1 to the observed femtosecond photochemical dynamics.

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Section: Resultssupporting

confidence: 79%

Section: Resultsmentioning

confidence: 99%

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Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C₁₁C₁₂ Torsion Coordinate

et al. 1998

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“…The necessary modifications were a reduction (increase) of the standard single (double) bond length and an increase (reduction) of the single (double) bond stretching and torsional force constants. The parameters were optimized to reproduce the crystal structure of 11-cis-retinal (Drikos et al, 1981). The modified force field parameters are given in Table 1 of the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Resonance Raman Examination of the Wavelength Regulation Mechanism in Human Visual Pigments

et al. 1997

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Resonance Raman spectra of recombinant human green and red cone pigments have been obtained to examine the molecular mechanism of color recognition by visual pigments. Spectra were acquired using a 77 K resonance Raman microprobe or preresonance Raman spectroscopy. The vibrational bands were assigned by comparison to the spectra of bovine rhodopsin and model compounds. The C=NH stretching frequencies of rhodopsin, the green cone pigment, and the red cone pigment in H2O (D2O) are found at 1656 (1623), 1640 (1618), and 1644 cm(-1), respectively. Together with previous resonance Raman studies on iodopsin [Lin, S. W., Imamoto, Y., Fukada, Y., Shichida, Y., Yoshizawa, T., & Mathies, R. A. (1994) Biochemistry 33, 2151-2160], these values suggest that red and green pigments have very similar Schiff base environments, while the Schiff base group in rhodopsin is more strongly hydrogen-bonded to its protein environment. The absence of significant frequency and intensity differences of modes in the fingerprint and the hydrogen out-of-plane wagging regions for all these pigments does not support the hypothesis that local chromophore interactions with charged protein residues and/or chromophore planarization are crucial for the absorption differences among these pigments. However, our data are consistent with the idea that the Schiff base group in blue visual pigments is stabilized by protein and water dipoles and that the removal of this dipolar field shifts the absorption maximum from blue to green. A further red shift of the lambda(max) from the green to the red pigment is successfully modeled by the addition of hydroxyl-bearing amino acids (Ser164, Tyr261, and Thr269) close to the ionone ring that lower the transition energy by interacting with the change of dipole moment of the chromophore upon excitation. The increased hydrogen bonding of the protonated Schiff base group in rhodopsin is predicted to account for the 30 nm blue shift of its absorption maximum compared to that of the green pigment.

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“…analysis, including N.O.E., has identified the 12-s-cis conformation for the dimethyl ester of 12-carboxyretinoic acid (127).189 A study of lH and 13C n.m.r. spectra showed that the x-bond orders in the retinylidene Schiff-base (230) were unchanged relative to those in retinaldehyde; conversion into the protonated Schiff-base form (231) caused a substantial change in the bond orders.lg0 Effects of solvent on the 13C n.m.r. spectra of isomers of retinaldehyde have been studied, l 9 and calculations of the conformation of trans-retinaldehyde were in agreement with results of n.m.r.…”

Section: Separation and Assaymentioning

confidence: 99%

Carotenoids and polyterpenoids

Britton

1984

Nat. Prod. Rep.

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A second crystal form of 11‐cis, 12‐cis retinal, the chromophoric group in visual pigments

Cited by 17 publications

References 24 publications

Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C₁₁C₁₂ Torsion Coordinate

Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C₁₁C₁₂ Torsion Coordinate

Resonance Raman Examination of the Wavelength Regulation Mechanism in Human Visual Pigments

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A second crystal form of 11‐cis, 12‐cis retinal, the chromophoric group in visual pigments

Cited by 17 publications

References 24 publications

Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C11C12 Torsion Coordinate

Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C11C12 Torsion Coordinate

Resonance Raman Examination of the Wavelength Regulation Mechanism in Human Visual Pigments

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Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C₁₁C₁₂ Torsion Coordinate

Vibrational Assignment of Torsional Normal Modes of Rhodopsin: Probing Excited-State Isomerization Dynamics along the Reactive C₁₁C₁₂ Torsion Coordinate