Excitation Spectroscopy of Retinal and Related Polyenes†

Christensen, Ronald L.; Kohler, Bryan E.

doi:10.1111/j.1751-1097.1974.tb06532.x

Cited by 48 publications

(20 citation statements)

References 36 publications

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“…However, although K' may not be known precisely, estimates of its range and hence R, may be reasonably made. There is considerable experimental evidence that the retinylidene chromophore has its long axis tilted 17" to the plane of the purple membrane surface (Dencher, 1983) and also it is predicted that this molecular axis coincides with the electronic absorption moment of retinal (Moore and Song, 1973;Christensen and Kohler, 1974). Emission from Trp has been shown to result from two orthogonal states which are rapidly equilibrated at room temperature and which are coplanar with the aromatic ring system (Andrews and Forster, 1974).…”

Section: Resultsmentioning

confidence: 99%

Alkaline Quenching of Bacteriorhodopsin Tryptophanyl Fluorescence: Evidence for Aqueous Accessibility or a Hydrogen‐bonded Chain

Palmer¹,

Sherman²

1985

Photochem & Photobiology

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Abstract— Comparison between Trp fluorescence yields of membrane‐bound bacteriorhodopsin (BR) and retinylidene‐free bacterioopsin (BO) is consistent with a model in which all eight Trp residues are active fiuorophores in the latter, while the emission of all but two residues in the former is lost by energy transfer to retinal. The visible chromophore of BR is progressively bleached with increasing pH. Up to pH 12 this bleaching is reversed on reneutralization; but above this the change is irreversible with the appearance of a new absorption band characteristic of free retinal. Emission yields for both proteins decrease with increasingly alkaline pH in a manner typical of energy transfer to weakly‐fluorescent tyrosinate. The limiting yields, reached at a pH corresponding to that producing irreversible bleaching of the visible chromophore, agree with an integral value of one remaining active Trp fluorophore in BR and between one and two in BO and show that the bulk of Trp are within the 11 Å Förster energy‐transfer distance of Tyr accessible to OH−. Current models of the native protein structure of BR arrange the polypeptide chain primarily in a bundle of seven helical segments with axes perpendicular to the lipid bilayer plane and with buried polar residues, including Trp and Tyr, located at intrahelical surfaces. An interpretation of the observed accessibility of buried Tyr to OH− is that an aqueous region exists within the protein structure. Moreover, this putative aqueous region must be close to the retinylidene chromophore and thus may be associated with the light‐driven ion transport system. The results are also compatible with energy transfer to internal Tyr residues which are connected via a chain of phenolate hydrogen bonds to a surface Tyr.

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Section: Resultsmentioning

confidence: 99%

Alkaline Quenching of Bacteriorhodopsin Tryptophanyl Fluorescence: Evidence for Aqueous Accessibility or a Hydrogen‐bonded Chain

Palmer¹,

Sherman²

1985

Photochem & Photobiology

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“…They found that the 'na* state is much higher in energy than was previously expected, the (0-0) band being located at -30,000 cm-', about 3,000 cm-' above the main 'B, band. This finding requires a reinterpretation of the argument put forth by Christensen and Kohler [7] to explain the wavelength dependence of fluorescence excitation, in which the 'na* state is taken to lie below the 'B, state.…”

Section: Introductionmentioning

confidence: 87%

“…The cis-band corresponds to a 'A: t ' A ; transition, which is forbidden in linear EAPs, but becomes allowed when cis or s-cis conformations are present. A final low intensity Based on the wavelength dependence of the fluorescence excitation spectrum of all-trans retinal and several closely related molecules, Christensen and Kohler [7] have proposed the existence of a weakly absorbing ' A; state at lower energy than the intense 'B, state, although Songet al [8] have proposed an alternative explanation in which the 'B, state is lowest. The spectral broadness of the 'B, band makes direct observation of a ' A ; state quite difficult.…”

Section: Introductionmentioning

confidence: 99%

Excited states of all-trans and 11-cis retinal: All valence-electron SCF-MO-CI calculations

Weimann

Maggiora

Blatz

2009

Int. J. Quantum Chem.

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All valenceelectron (CNDO/S) SCF-MO-CI calculations are carried out on the excited states of a number of conformers of ull-rruns and 1 1 -cis retinal. Singlet state transition energies, oscillator strengths, polarization directions, and ground and excited state dipole moments are examined, and the relationship of the retinal ' n d states to polyene Inn* states is analyzed. Particular emphasis is given to the nature and location of the cis-hand, and to the relative location of the Inn* and 'B, states. Several aspects of the electronic structure of triplet states are also examined.

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“…Energy transfer from the bases to Eu2+ has been used to probe the location of metal binding sites on tRNA [97,98]. Energy transfer in synthetic compounds containing both a pyrimidine base and a fluorescent dye has also been studied [9]. However, the problem of intramolecular energy transfer between bases in polynucleotides and nucleic acids at room temperature remains an open question.…”

Section: Spectroscopy Of Nucleic Acidsmentioning

confidence: 99%

Excited States of Nucleic Acids

Favre

Vigny

1975

Photochem & Photobiology

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The literature on the electronic excited states of nucleic acids is reviewed covering the period approximately of mid 1973-mid 1975. Our interest focuses on the nucleic acids themselves as well as on their components and derivatives from two points of view which are closely related: (i) their spectroscopic properties, and (ii) their photochemical properties. The photobiological aspects of nucleic acids will not be considered here, however. Spectroscopy of nucleic acidsVery few papers have been concerned with the investigation of the excited singlet states of nucleic acid bases at high resolution. Sharp absorption and emission spectra are reported for crystalline purine at 4 K and an interpretation of the pattern of the excited singlet states is given using molecular orbital calculations and correlations with pyrimidine and aza substituted derivatives [63]. A study of the polarized singlecrystal reflection spectra of 6-azauracil shows that the 260 nm absorption band can be resolved into two bands [S]. Higher excited singlet states of nucleic acid bases have been investigated in thin films 1911 and the energy diagrams have been evaluated both in the neutral and ionized state [SS]. Theoretical calculations of the energies of the lower-out-of-plane transitions of the nucleic acid bases, their tautomers and ions have been made using the CNDO-CI method [35]. The CND0/2 method has also been used for these molecules [ 1011 and thiouracils [25].Studies of the fluorescence and phosphorescence emission of nucleic acids in water-alcohol glasses at low temperature, where the quantum yields are high, have received less emphasis than previously. In the case of the dinucleotide C3fP5C, the fluorescence polarimtion has been interpreted in terms of a charge resonance in the excimer state [lo]. Further work has been reported on the triplet emission of DNA [45] and yeast tRNAPhe [34]. In that case, the triplet emission of Ado can be observed at 1.2 K, but not at 77 K, partially due to energy transfer to the "Y" base. Energy transfer in Ado frozen aggregates to appropriate traps has been demonstrated [49] as well as triplet-triplet energy transfer from the bases to tryptophan in oligopeptide, poly rA (or DNA) complexes [33]. The large previously observed enhancement in the phosphorescence of DNA when Agf

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Excitation Spectroscopy of Retinal and Related Polyenes†

Cited by 48 publications

References 36 publications

Alkaline Quenching of Bacteriorhodopsin Tryptophanyl Fluorescence: Evidence for Aqueous Accessibility or a Hydrogen‐bonded Chain

Alkaline Quenching of Bacteriorhodopsin Tryptophanyl Fluorescence: Evidence for Aqueous Accessibility or a Hydrogen‐bonded Chain

Excited states of all-trans and 11-cis retinal: All valence-electron SCF-MO-CI calculations

Excited States of Nucleic Acids

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