Consequences of H-dimerization on the photophysics and photochemistry of oxacarbocyanines

Caselli, Monica; Latterini, Loredana; Ponterini, Glauco

doi:10.1039/b316424a

Cited by 23 publications

(27 citation statements)

References 25 publications

(64 reference statements)

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“…In aqueous solution, the dye OCC displays a tendency toward aggregation and forms fl uorescent H-dimers, the fl uorescence quantum yield of which is comparable with that for the monomer [19]. In the absorption spectra for an OCC concentration of 1.6·10 -6 mol/L, we observe some contribution from the absorption of the dimers in the ~470 nm region ( Fig.…”

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confidence: 58%

“…Results and Discussion. The spectral fl uorescence properties of OCC, cis-trans photoisomerization, and also formation of dimer aggregates of the dye in solutions have been studied previously in [19]. The lack of rigidity in polymethine dye molecules means that isomerization is possible as a result of rotation about the polymethine chain.…”

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confidence: 97%

“…In nonpolar dioxane, the width of the band is markedly smaller, σ abs = 876 cm -1 ( Table 1). The differences in the positions of the maxima and the "centers of gravity" in the fl uorescence excitation spectra relative to the absorption spectra, and also the broader bands in the absorption spectra in polar solvents are obviously due to the fact that in solution, along with the original trans-isomer of OCC, there is a substantial amount of the cis-isomer of the dye, absorbing in a longer wavelength region than the trans form [19]. A decrease in the polarity of the solvent (acetone-dioxane) is accompanied by a 10-fold increase in the fl uorescence of the dye OCC ( Table 1).…”

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confidence: 97%

“…The lack of rigidity in polymethine dye molecules means that isomerization is possible as a result of rotation about the polymethine chain. We know that in aqueous and aqueous/alcoholic solutions, OCC is mainly found as the trans isomer [19]. For meso-substituted thiacarbocyanine dyes, a dynamic trans-cis equilibrium is typical, depending on the polarity of the medium [20,21].…”

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confidence: 99%

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Spectral Fluorescence Properties of an Anionic Oxacarbocyanine Dye in Complexes with Human Serum Albumin

Пронкин

Татиколов

2015

J Appl Spectrosc

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The spectral fl uorescence properties of the anionic oxacarbocyanine dye 3, were studied in solutions and in complexes with human serum albumin (HSA). Interaction with HSA leads to a signifi cant increase in the fl uorescence of the dye. We studied quenching of the fl uorescence of OCC in a complex with HSA by ibuprofen and warfarin. Data on quenching of fl uorescence by ibuprofen indicate binding of the dye to binding site II of subdomain IIIA in the HSA molecule. Synchronous fl uorescence spectra of human serum albumin in the presence of OCC showed that complexation with OCC does not lead to appreciable rearrangement of the protein molecule at the binding site.Keywords: oxacarbocyanine dyes, human serum albumin, noncovalent complex, spectral fl uorescence properties, method of moments, synchronous fl uorescence spectra.Introduction. Serum albumins are major transport proteins in vertebrates. Their principal function (transport of biological metabolites) is based on the ability of these proteins to form intermolecular complexes with different compounds [1,2], where the major role is usually played by Coulomb and hydrophobic interactions [3]. The same ability of serum albumins is the basis for application of spectral fl uorescent probes for detecting these proteins in biological samples and artifi cial systems [4,5]. Dye probes that bind non-covalently to the albumin molecule show a change in spectral fl uorescence properties, which lets us detect even low concentrations of the biopolymer. Polymethine (cyanine) dyes are of special interest in this respect [4].It was shown earlier [4, 6-8] that anionic thiacarbocyanine dyes 3,3'-di-(γ-sulfopropyl)-9-methylthiacarbocyanine betaine, 3,3'-di-(γ-sulfopropyl)-4,5,4',5'-dibenzo-9-ethylthiacarbocyanine betaine form stable complexes with albumins with high binding constants; interaction with proteins is accompanied by a shift in the cis-trans equilibrium toward the trans isomers of the dyes and a dramatic increase in the fl uorescence quantum yield. Tricarbocyanine dyes with indole heterocycles are widely used as spectral fl uorescent probes in biological tissues [4,9]. However, the effect of interaction with proteins on the spectral fl uorescence properties of oxacarbocyanine dyes has remained virtually unstudied.In this work, we have studied the effect of non-covalent interaction with human serum albumin (HSA) on the spectral fl uorescence properties of the anionic meso-substituted oxacarbocyanine dye 3,3'-di-(γ-sulfopropyl)-5,5'-diphenyl-9-ethyloxacarbocyanine betaine with a pyridinium cation (OCC), with the aim of determining the potential of OCC as a dye probe for measuring HSA in solutions.The Experiment. We used the dye OCC, provided by Professor B. I. Shapiro (Khimfotoproekt Research Institute), commercial HSA (Sigma-Aldrich, USA); as the solvents, we used dioxane, acetone, isopropanol, dimethylsulfoxide (analytical grade), and distilled water. The dye solutions were prepared immediately before the measurements.The absorption spectra of the dyes were measured on ...

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confidence: 97%

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Spectral Fluorescence Properties of an Anionic Oxacarbocyanine Dye in Complexes with Human Serum Albumin

Пронкин

Татиколов

2015

J Appl Spectrosc

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“…For example, dimerization brought about 20-fold deceleration of the deactivation from the singlet-excited state for oxacarbocyanines [21], whereas almost 9-fold slowing down was found for a merocyanine dye [22]. The coralyne monomer and dimer had 9.7 and 40.7 ns fluorescence decay times, respectively [18].…”

Section: Effect Of Dimerization On the Fluorescence Characteristicsmentioning

confidence: 99%

The origin of the dual fluorescence of protonated ellipticine in water

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Biczók

Jablonkai

2016

Chemical Physics Letters

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Absorption and fluorescence spectroscopic measurements, as well as isothermal calorimetric titrations showed that the biexponential decay kinetics of protonated ellipticine (EH + )fluorescence in water originates from dimerization. Due to the high equilibrium constant for the association of two EH + and the intense fluorescence of the dimer, deviation from the exponential emission intensity decay commences below micromolar concentrations. Dimerization must be taken into account when EH + concentration is determined by spectrophotometry, and when EH + binding to substrates are studied. The molar absorption coefficients of the monomer and dimer were determined.

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Disruption of Protein-Protein Interfaces

Mangani¹

2013

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Consequences of H-dimerization on the photophysics and photochemistry of oxacarbocyanines

Cited by 23 publications

References 25 publications

Spectral Fluorescence Properties of an Anionic Oxacarbocyanine Dye in Complexes with Human Serum Albumin

Spectral Fluorescence Properties of an Anionic Oxacarbocyanine Dye in Complexes with Human Serum Albumin

The origin of the dual fluorescence of protonated ellipticine in water

Disruption of Protein-Protein Interfaces

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