Color effects in pressure-tuned hole-burned spectra

Gradl, G.; Zollfrank, J.; Breinl, W.; Friedrich, J.

doi:10.1063/1.460148

Cited by 46 publications

(53 citation statements)

References 12 publications

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“…p -o 1 would imply that there were no pressure broadening; hence, the obvious conclusion would be that pa-1 is unrealistic. However, from all that we know from numerous experiments on glasses (27)(28)(29)(30), this is not the case. If p = 1 is possible, where does the broadening r come from?…”

mentioning

confidence: 79%

“…Previous studies measured compressibilities by using the hole-burning technique to study MP-HRP at pH 5 (22), protoprophyrin-substituted myoglobin (24), and a series of alcohol glasses doped with several dyes (27,(29)(30)(31). We stress that the results obtained fit well into the scenario known from other experiments, such as sound velocity measurements (32), Brillouin scattering (33), and mechanical experiments (34).…”

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confidence: 99%

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Spectral hole burning and selection of conformational substates in chromoproteins.

Friedrich

Gafert

Zollfrank

et al. 1994

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

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We investigated spectral holes burnt at 1.5 K into the origins of several tautomeric forms of mesoporphyrin IX-substituted horseradish peroxidase at pH 8 under pressures up to 2 MPa. From the pressure-induced lineshift the compressibility of the apoprotein could be determined. We found that the compressibility changed significantly when measured at different tautomer origins. It was concluded that there must be a correlation between the tautomer configurations of the chromophore and the actual structures of the apoprotein. As a consequence, specific conformational substates of the protein can be selected by optical selection of the associated tautomers.The solid-state physics of proteins is an intriguing field. Unlike crystals, proteins are finite systems, yet they have a smooth density of vibrational states which is Debye-like at sufficiently small energies (1). Like crystals, proteins are highly ordered (2). Yet disorder plays a very important role, too (3, 4). Disorder manifests itself in inhomogeneously broadened spectral lines, in nonexponential kinetics, in nonArrhenius-type activated processes, in a glass-like specific heat, in dielectric damping, etc. (5-8). Even from x-ray scattering experiments, it became obvious that, at a sufficiently high level of resolution, the structure of a protein is not so well defined (2, 3). There seems to be agreement that a certain extent of structural disorder is a prerequisite for the proper functioning of a protein.A possible model for describing the relation between order and disorder in proteins is based on the concept of conformational substates (4,7,9,10): The basic idea of this model is that a protein can exist in a huge set of substates. Most of these substates are assumed to be in fast equilibrium because their separating barriers are sufficiently small compared with kT. Some ofthem, however, are nonequilibrium states. These special substates may be functionally important. It is structural disorder which gives enough freedom to the protein to reorganize its structure for specific requirements.Here we address the problem of how this reorganization takes place and how this is related to the prosthetic group. Can a slight structural change of the prosthetic group, as induced by a weak chemical interaction, be a signal for the protein structure to be rearranged, for example, to help the binding of special molecules? That is, we address the problem of correlation between the configurations of the prosthetic group and the conformational substates of the protein.The experimental technique we employ is persistent spectral hole burning (11)(12)(13)(14)(15). Hole burning is a special type of saturation spectroscopy. Its specific feature, as compared with similar techniques in NMR and ESR spectroscopy, is the persistence of the hole. This persistence is the reason why the technique can be used to study the ground state by optical means. At liquid-helium temperatures, the width of a spectral hole is close to the natural width of the optical transition involved. For m...

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confidence: 79%

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confidence: 99%

Spectral hole burning and selection of conformational substates in chromoproteins.

Friedrich

Gafert

Zollfrank

et al. 1994

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

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“…(4). The a to a T ratio taken with a minus sign would give the power coefficient of r if a single potential function were responsible for the solvent shift [13,32]. A steep frequency dependence of pressure shifts for 3,4-BP in ethanol glass [(6.270.4) Â 10 À5 bar À1 ] (Fig.…”

Section: Impurity Spectra and Disorder In Glasses And Crystalsmentioning

confidence: 98%

“…3) [16,17,32]. The slope a has initially been used to calculate the compressibility a T , based on the inference that solely dispersive interaction is responsible for the band shift and broadening [32].…”

Section: Impurity Spectra and Disorder In Glasses And Crystalsmentioning

confidence: 99%

Impurity spectroscopy in glasses and disordered crystals: Inhomogeneous broadening and electron phonon coupling

Renge

2008

Journal of Luminescence

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“…[1][2][3][4][5][6][7][8] Hole broadening, observable in pressure-tuning experiments, reflects the inherent inhomogeneity ͑dispersion of pressure coefficients͒ of the subensemble of molecules with a fixed transition energy. Such broadening is especially large in disordered solids such as glasses, where its magnitude is comparable to that of the pressure-induced spectral shift.…”

Section: Introductionmentioning

confidence: 99%

Diaelastic pressure-induced effects on spectral holes in crystals

Kikas

Leiger

1996

The Journal of Chemical Physics

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Phase behaviour of a symmetric binary mixture of hard rodsA statistical theory is developed in order to describe the pressure-induced shift and broadening of spectral holes in pressure-tuning experiments in crystals. The theory accounts for the defect-related diaelastic effect ͑induction of internal inhomogeneous strain fields by the applied hydrostatic pressure due to the host-defect compressibility and/or size mismatch͒. General results are specified and analyzed in the case of similar defects and for two different types of point defects. The former case yields no hole broadening, while the latter one does. A similar consideration applies to electricand magnetic-field-induced effects on spectral holes in crystals as well.

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Color effects in pressure-tuned hole-burned spectra

Cited by 46 publications

References 12 publications

Spectral hole burning and selection of conformational substates in chromoproteins.

Spectral hole burning and selection of conformational substates in chromoproteins.

Impurity spectroscopy in glasses and disordered crystals: Inhomogeneous broadening and electron phonon coupling

Diaelastic pressure-induced effects on spectral holes in crystals

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