Morphologie et propriétés optiques des cristaux de lysozyme de poule de type quadratique et orthorhombique

Cervelle, Bernard; Cesbron, Fabien; Berthou, J.; Jolles, Paul Rudolf

doi:10.1107/s0567739474001550

Cited by 25 publications

(17 citation statements)

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“…This requirement was not met in the experiments presented here. The refractive index of the lysozyme crystals and fluoresceinmother liquor solutions were 1.53 -1.58 (Caylor et al, 2001;Cervelle et al, 1974) and around 1.33 -1.34 (Fredericks et al, 1994), respectively. These differences were so large that by adding a versatile dipolar solvent, dimethylsulfoxide, (Kluijtmans et al, 1998) or D-glucose (Malmsten et al, 1999) to the solution, matching of the refractive indexes of solid and liquid could not be achieved in our case.…”

Section: Resultsmentioning

confidence: 97%

Quantifying anisotropic solute transport in protein crystals using 3‐D laser scanning confocal microscopy visualization

Cvetkovic

Straathof

Hanlon³

et al. 2004

Biotech & Bioengineering

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The diffusion of a solute, fluorescein into lysozyme protein crystals has been studied by confocal laser scanning microscopy (CLSM). Confocal laser scanning microscopy makes it possible to non-invasively obtain high-resolution three-dimensional (3-D) images of spatial distribution of fluorescein in lysozyme crystals at various time steps. Confocal laser scanning microscopy gives the fluorescence intensity profiles across horizontal planes at several depths of the crystal representing the concentration profiles during diffusion into the crystal. These intensity profiles were fitted with an anisotropic model to determine the diffusivity tensor. Effective diffusion coefficients obtained range from 6.2 x 10(-15) to 120 x 10(-15) m2/s depending on the lysozyme crystal morphology. The diffusion process is found to be anisotropic, and the level of anisotropy depends on the crystal morphology. The packing of the protein molecules in the crystal seems to be the major factor that determines the anisotropy.

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Section: Resultsmentioning

confidence: 97%

Quantifying anisotropic solute transport in protein crystals using 3‐D laser scanning confocal microscopy visualization

Cvetkovic

Straathof

Hanlon³

et al. 2004

Biotech & Bioengineering

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“…We interpret this abrupt change in the appearance of the crystal as follows. The refractive index of the solvent varies between $1.33 (water) and $1.38 (40% glycerol); the refractive index of the crystal is likely near n ' 1.56 measured for tetragonal lysozyme (Cervelle et al, 1974); and the refractive index for Paratone oil is likely near the n = 1.52 of NVH oil. If there is a layer of solvent coating the crystal, it creates two interfaces, oil-solvent and solventcrystal, with large (Án ' 0.15) refractive index steps.…”

Section: Methodsmentioning

confidence: 95%

“…We interpret this abrupt change in the appearance of the crystal as follows. The refractive index of the solvent varies between $1.33 (water) and $1.38 (40% glycerol); the refractive index of the crystal is likely near n ' 1.56 measured for tetragonal lysozyme (Cervelle et al, 1974) (c) The remaining mother liquor, which tends to form beads (indicated by the arrow), is scraped off with a MicroChisel. (d) When all the external solvent has been removed, the crystal becomes nearly invisible in the oil, indicating that the solvent layer is no thicker than the wavelength of illuminating light.…”

Section: Methodsmentioning

confidence: 99%

Slow cooling of protein crystals

Warkentin¹,

Thorne²

2009

J Appl Crystallogr

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Cryoprotectant-free thaumatin crystals have been cooled from 300 to 100 K at a rate of 0.1 K s À1 -10 3 -10 4 times slower than in conventional flash coolingwhile continuously collecting X-ray diffraction data, so as to follow the evolution of protein lattice and solvent properties during cooling. Diffraction patterns show no evidence of crystalline ice at any temperature. This indicates that the lattice of protein molecules is itself an excellent cryoprotectant, and with sodium potassium tartrate incorporated from the 1.5 M mother liquor ice nucleation rates are at least as low as in a 70% glycerol solution. Crystal quality during slow cooling remains high, with an average mosaicity at 100 K of 0.2 . Most of the mosaicity increase occurs above $200 K, where the solvent is still liquid, and is concurrent with an anisotropic contraction of the unit cell. Near 180 K a crossover to solid-like solvent behavior occurs, and on further cooling there is no additional degradation of crystal order. The variation of B factor with temperature shows clear evidence of a protein dynamical transition near 210 K, and at lower temperatures the slope dB/dT is a factor of 3-6 smaller than has been reported for any other protein. These results establish the feasibility of fully temperature controlled studies of protein structure and dynamics between 300 and 100 K.

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“…32 The refractive index of the protein, n p ≃ 1.55, is from Ref. 50. Figure 5 presents the calculations of the change in the absorption coefficient of the solution with increasing the volume fraction of the solute according to Eq.…”

Section: Comparison To Experimentsmentioning

confidence: 99%

Terahertz absorption of lysozyme in solution

Martin

Matyushov

2017

The Journal of Chemical Physics

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Absorption of radiation by solution is described by its frequency-dependent dielectric function and can be viewed as a specific application of the dielectric theory of solutions. For ideal solutions, the dielectric boundary-value problem separates the polar response into the polarization of the void in the liquid, created by the solute, and the response of the solute dipole. In the case of a protein as a solute, protein nuclear dynamics do not project on significant fluctuations of the dipole moment in the terahertz domain of frequencies and the protein dipole can be viewed as dynamically frozen. Absorption of radiation then reflects the interfacial polarization. Here we apply an analytical theory and computer simulations to absorption of radiation by an ideal solution of lysozyme. Comparison with the experiment shows that Maxwell electrostatics fails to describe the polarization of the protein-water interface and the “Lorentz void,” which does not anticipate polarization of the interface by the external field (no surface charges), better represents the data. An analytical theory for the slope of the solution absorption against the volume fraction of the solute is formulated in terms of the cavity field response function. It is calculated from molecular dynamics simulations in good agreement with the experiment. The protein hydration shell emerges as a separate sub-ensemble, which, collectively, is not described by the standard electrostatics of dielectrics.

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Morphologie et propriétés optiques des cristaux de lysozyme de poule de type quadratique et orthorhombique

Cited by 25 publications

References 0 publications

Quantifying anisotropic solute transport in protein crystals using 3‐D laser scanning confocal microscopy visualization

Quantifying anisotropic solute transport in protein crystals using 3‐D laser scanning confocal microscopy visualization

Slow cooling of protein crystals

Terahertz absorption of lysozyme in solution

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