Fluorescence, resonance Raman, and radiationless decay in several hemoproteins

Adar, Fran; Gouterman, Martin; Aronowitz, S.

doi:10.1021/j100561a010

Cited by 83 publications

(65 citation statements)

References 13 publications

(19 reference statements)

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“…As in room-temperature studies (7,17,18), relaxed fluorescence can also be seen in our spectra. See spectrum E especially.…”

Section: Resultssupporting

confidence: 86%

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Excited state lifetimes in cytochromes measured from Raman scattering data: evidence for iron-porphyrin interactions.

Friedman¹,

Rousseau²,

Adar³

1977

Proc. Natl. Acad. Sci. U.S.A.

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ABSTRACr Resonance Raman scattering excitation profile data have been obtained on ferrocytochromes c and b5 in the a absorption band region. We observe in cytochrome c that the shape of the excitation profile agrees with the absorption band shape, while in cytochrome b5 it does not. In addition, we observe in cytochrome b5 a linewidth substantially larger than that in cytochrome c. From our data we conclude that the excited state lifetime in cytochrome c is longer than that in cytochrome b5 and that in cytochrome b5 the relaxation of the 1r-7r* excited state configuration of the porphyrin ring is different in the x direction than in the y direction. Possible origins of these effects due to coupling to the d-d transitions of the iron atom are discussed. strumentation utilizing dye laser sources to obtain tunability in the excitation frequency over the range of the a-band. To obtain the excitation profiles the intensities of the hemeprotein, Raman lines were compared to the intensity of either the ice Raman lines or the strong Raman line at 981 cm-1 of S042-[(NH4)2S04] that was added as a Raman intensity reference.Low-temperature absorption spectra were obtained by looking at the spectrum of white light scattered from the frozen sample and comparing it with the light scattered from a diffuse scatterer as well as by conventional transmission techniques using a Cary 15 spectrometer.The molecular and electronic properties of heme proteins have been heavily studied by a wide variety of techniques in an effort to understand on a molecular level the mechanisms of the oxidation-reduction processes. Most electronic structure information about the porphyrin macrocycle of these proteins has been obtained from the analysis of absorption (1) and fluorescence (2) data, but more recently several groups (refs. 3-10 and references cited in ref. 8) have applied the technique of resonance Raman scattering to these systems to determine molecular symmetry and electronic structure properties. In this study we have examined the well-known splitting of the a-absorption band in heme proteins by obtaining resonance Raman excitation profile data, i.e., the intensity of the Raman scattering as the excitation frequency is tuned through the absorption band. The a-bands of both ferrocytochrome c and ferrocytochrome bswere investigated. Our data demonstrate that the excited state lifetime resulting from the Qo,o transition (a-band) is shorter in cytochrome bs than it is in cytochrome c. They also show that in cytochrome b5 the excited state lifetimes of the split a-band differ substantially. Such a lifetime difference is absent in cytochrome c. We discuss possible explanations for these differences in terms of nonradiative relaxation via d-d transitions. METHODS AND MATERIALSCytochrome b5 was prepared from calves liver by the method of Omura and Takesue (11). It consists of protoporphyrin IX iron(II) in which the iron atom is bound to the protein through histidine ligands (12). Cytochrome c was purchased commercially (Sigma type VI). The iron ...

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“…As in room-temperature studies (7,17,18), relaxed fluorescence can also be seen in our spectra. See spectrum E especially.…”

Section: Resultssupporting

confidence: 86%

“…If the band were primarily inhomogeneously broadened, the relaxed fluorescence would also be sharp. Furthermore, the low quantum yield for re-emission (17,18) indicates a very short nonradiative lifetime, which is consistent with a large homogeneous broadening and inconsistent with an inhomogeneous distribution of sharp absorption lines.…”

Section: Resultsmentioning

confidence: 85%

Excited state lifetimes in cytochromes measured from Raman scattering data: evidence for iron-porphyrin interactions.

Friedman¹,

Rousseau²,

Adar³

1977

Proc. Natl. Acad. Sci. U.S.A.

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“…Our initial work on the succinate cytochrome c reductase showed it to be a fruitful system for RR study for a variety of reasons: (1) RR spectra of isolated cytochromes exhibit well-defined marker bands [7] ; (2) The RR quantum yields of ferrous cytochromes are unusually large (lo-') [25] ; (3) The spectroscopic characterization of the RR effect in ferrous cytochromes is highly developed [17-191. * To whom correspondence should be directed…”

Section: Introductionmentioning

confidence: 99%

Spectral evidence for interactions between membrane‐bound hemes: Resonance Raman spectra of mitochondrial cytochrome b–c₁ complex as a function of redox potential

Adar¹,

Erecińska²

1977

FEBS Letters

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“…The resulting dispersion curve depends on both total dephasing and population decay rates, thereby demonstrating a general method for the determination of subpicosecond relaxation processes in systems to which the model is applicable. Theoretical fits to the results for iron(III) tetraphenylporphyrin chloride imply that the Soret transition is essentially homogeneously broadened with a total dephasing width of 900 4 200 cm-l, and it is argued that the population decay time in this case is approximately 3.5 fsec. The broad linear absorption spectrum of the Soret and is interpreted as resulting from intramolecular perturbations between the Soret and lower energy excited states of iron(III) tetraphenylporphyrin chloride.…”

mentioning

confidence: 97%

“…The consistent observation of broad optical spectral bands for these systems has led to suggestions that they may actually be homogeneous, with widths representing the coupling of the porphyrin states with the lower lying electronic states (1)(2)(3)(4)(5)(6). The lowest excited states of filled shell metalloporphyrins manifest sharp spectral bands and correspondingly long excited-state life times.…”

mentioning

confidence: 98%

Femtosecond relaxation of an iron porphyrin observed with polarization spectroscopy in a three-level system

Andrews

Hochstrasser

1980

Proc. Natl. Acad. Sci. U.S.A.

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An experimental and theoretical study is presented of the nonlinear response of a dilute solution being pumped by two laser fields having different frequencies w1 and (02 that are both in resonance with electronic transitions of the solute. Experimental results were obtained for the dispersion of the third-order susceptibility IX(3kW2) 2 for a dilute solution of iron (III) The metalloporphyrins have been recognized for some time as systems that may undergo extremely rapid relaxation after optical excitation. The consistent observation of broad optical spectral bands for these systems has led to suggestions that they may actually be homogeneous, with widths representing the coupling of the porphyrin states with the lower lying electronic states (1-6). The lowest excited states of filled shell metalloporphyrins manifest sharp spectral bands and correspondingly long excited-state life times. Similarly, with other types of moderately large molecules the higher excited levels usually show broad spectra characteristic of the perturbations between the different electronic surfaces (7,8). In molecules that have nearby states and large numbers of vibrational modes, we can expect that electronic relaxations occurring in these perturbation regions will be very complex in the time domain and extremely rapid when excited with sufficiently short pulses.In the present study we have used polarization spectroscopy to investigate directly the relaxation of iron(III) tetraphenylporphyrin chloride (FeTPP) in solution. Polarization spectroscopy involves the detection of nonlinear polarization in the medium at one frequency while the system is being pumped by another optical field. This approach has previously been used with gases of atoms and small molecules to expose Doppler free spectra in inhomogeneously broadened systems (9). In solutions, polarization spectroscopy is expected to provide new information about the dynamics and inhomogeneous structure of liquids. Experiments with the two incident fields having nearly equal frequency were discussed by Yajima (10) and carried out by Yajima and Souma (11). These authors made observations of coherently generated light at 2w1-2 (where 01 W2) and related the signals to homogeneous widths and population decays of the resonant levels in a liquid. Song et al. (12) obtained ultrafast relaxation times in solutions by measuring the coherently generated light at W2 when pumping with two sources w, and W2, again where w, i 2The interpretation of previous measurements in liquids (10)(11)(12) assumed that the inhomogeneous line broadening is the dominant contribution to the widths of optical transitions of dyes in solutions. Whereas this may be true in certain cases, there is no reason to expect it to be valid in general, and one purpose of the present work was to evaluate approximations of this type by considering a system where there is more knowledge of the molecular spectroscopy and internal molecular dynamics. Optically pumped molecules in solutions can undergo population relaxatio...

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Fluorescence, resonance Raman, and radiationless decay in several hemoproteins

Cited by 83 publications

References 13 publications

Excited state lifetimes in cytochromes measured from Raman scattering data: evidence for iron-porphyrin interactions.

Excited state lifetimes in cytochromes measured from Raman scattering data: evidence for iron-porphyrin interactions.

Spectral evidence for interactions between membrane‐bound hemes: Resonance Raman spectra of mitochondrial cytochrome b–c₁ complex as a function of redox potential

Femtosecond relaxation of an iron porphyrin observed with polarization spectroscopy in a three-level system

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Fluorescence, resonance Raman, and radiationless decay in several hemoproteins

Cited by 83 publications

References 13 publications

Excited state lifetimes in cytochromes measured from Raman scattering data: evidence for iron-porphyrin interactions.

Excited state lifetimes in cytochromes measured from Raman scattering data: evidence for iron-porphyrin interactions.

Spectral evidence for interactions between membrane‐bound hemes: Resonance Raman spectra of mitochondrial cytochrome b–c1 complex as a function of redox potential

Femtosecond relaxation of an iron porphyrin observed with polarization spectroscopy in a three-level system

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Spectral evidence for interactions between membrane‐bound hemes: Resonance Raman spectra of mitochondrial cytochrome b–c₁ complex as a function of redox potential