Permeability of lysozyme tetragonal crystals to water

Морозов, В. Н.; Качалова, Г.С.; Evtodienko, V.U.; Lanina, N. F.; Morozova, Tamara Ya.

doi:10.1007/bf00211404

Cited by 34 publications

(45 citation statements)

References 17 publications

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“…The time for the lattice parameters to evolve and for the diffraction resolution to degrade increases with increasing crystal volume and thus decreasing surface-to-volume ratio. The characteristic time for the resolution to degrade to 3 A Ê ranges from <1 h for 0.1 mm 3 crystals to >4 h for 1 mm 3 crystals, roughly consistent with numerical estimates for diffusive equilibration between the crystal and salt solution (Fowlis et al, 1988;Morozov et al, 1995). Fig.…”

Section: Resultssupporting

confidence: 82%

“…signi®cant strain) during dehydration prior to the lattice transition suggests that appreciable gradients in water content do not develop within the crystal even though the lattice constants shrink by $2% in $1 h. This absence of gradients is consistent with estimates and measurements of diffusive water transport within the crystal (Fowlis et al, 1988;Morozov et al, 1995) and is consistent with the absence of signi®cant mosaic broadening and contrast in X-ray topographs before the lattice transition. The mosaic broadening and image contrast that develop once the diffraction resolution begins to degrade are thus likely to be associated with the lattice transition.…”

Section: Discussionsupporting

confidence: 74%

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Dynamic response of tetragonal lysozyme crystals to changes in relative humidity: implications for post-growth crystal treatments

Dobrianov

Kriminski

Caylor

et al. 2001

Acta Crystallogr D Biol Crystallogr

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The dynamic response of tetragonal lysozyme crystals to dehydration has been characterized in situ using a combination of X-ray topography, high-resolution diffraction lineshape measurements and conventional crystallographic diffraction. For dehydration from 98% relative humidity (r.h.) to above 89%, mosaicity and diffraction resolution show little change and X-ray topographs remain featureless. Lattice constants decrease rapidly but the lattice-constant distribution within the crystal remains very narrow, indicating that water concentration gradients remain very small. Near 88% r.h., the c-axis lattice parameter decreases abruptly, the steady-state mosaicity and diffraction resolution degrade sharply and topographs develop extensive contrast. This transformation exhibits metastability and hysteresis. At ®xed r.h. < 88% it is irreversible, but the original order can be almost completely restored by rehydration. These results suggest that this transformation is a ®rst-order structural transition involving an abrupt loss of crystal water. The front between transformed and untransformed regions may propagate inward from the crystal surface and the resulting stresses along the front may degrade mosaicity. Differences in crystal size, shape and initial perfection may produce the observed variations in degradation timescale. Consequently, the success of more general post-growth treatments may often involve identifying procedures that either avoid lattice transitions, minimize disorder created during such transitions or maintain the lattice in an ordered metastable state.

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Section: Resultssupporting

confidence: 82%

Section: Discussionsupporting

confidence: 74%

Dynamic response of tetragonal lysozyme crystals to changes in relative humidity: implications for post-growth crystal treatments

Dobrianov

Kriminski

Caylor

et al. 2001

Acta Crystallogr D Biol Crystallogr

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“…Association rate and shear rate control the adhesion in predictable ways: higher association rates and lower shear rates expand the adhesion envelope. The elasticity used in our simulations is ϭ 100 dyne⅐cm Ϫ1 , which is an average value for proteins (30). The Young modulus for proteins can vary greatly, however, from 10 11 dyne⅐cm…”

Section: Discussionmentioning

confidence: 99%

The state diagram for cell adhesion under flow: Leukocyte rolling and firm adhesion

Chang

Tees

Hammer

2000

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

258

226

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Leukocyte adhesion under flow in the microvasculature is mediated by binding between cell surface receptors and complementary ligands expressed on the surface of the endothelium. Leukocytes adhere to endothelium in a two-step mechanism: rolling (primarily mediated by selectins) followed by firm adhesion (primarily mediated by integrins). Using a computational method called ''Adhesive Dynamics,'' we have simulated the adhesion of a cell to a surface in flow, and elucidated the relationship between receptorligand functional properties and the dynamics of adhesion. We express this relationship in a state diagram, a one-to-one map between the biophysical properties of adhesion molecules and various adhesive behaviors. Behaviors that are observed in simulations include firm adhesion, transient adhesion (rolling), and no adhesion. We varied the dissociative properties, association rate, bond elasticity, and shear rate and found that the unstressed dissociation rate, k r o , and the bond interaction length, ␥, are the most important molecular properties controlling the dynamics of adhesion. Experimental k r o and ␥ values from the literature for molecules that are known to mediate rolling adhesion fall within the rolling region of the state diagram. We explain why L-selectinmediated rolling, which has faster k r o than other selectins, is accompanied by a smaller value for ␥. We also show how changes in association rate, shear rate, and bond elasticity alter the dynamics of adhesion. The state diagram (which must be mapped for each receptor-ligand system) presents a concise and comprehensive means of understanding the relationship between bond functional properties and the dynamics of adhesion mediated by receptor-ligand bonds.T rafficking of blood-borne cells into tissues is crucial to the proper function of the immune response. Inflammation, lymphocyte homing, and bone marrow replenishment after transplantation all depend on trafficking (1). Trafficking is mediated by receptor-mediated adhesion of blood-borne cells to the endothelial cells that line blood vessels. The transition from an unbound blood cell to an adherent one in flow involves a number of steps: initial tethering, transient ''rolling'' adhesion, and firm adhesion. Firm adhesion is usually followed by morphological changes and trans-endothelial migration into the tissue stroma, so that the cell can carry out its intended function within the tissue.Different adhesion molecules mediate different stages in this multistep adhesion process. Transient rolling adhesion occurs when receptor-ligand bonds between the leukocyte and endothelium exert a friction on the leukocyte, such that its velocity drops well below the hydrodynamic velocity for an unencumbered leukocyte at the same separation distance and wall shear rate. In the cell biology literature, rolling is often defined as a significant decrease in velocity, to perhaps 50% or less of the hydrodynamic velocity for cells near a surface, V H (2). Rolling is mediated by a variety of adhesion molecules, includ...

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“…This pore seems more like a series of pocket cavities. Such a pore is not remarkable as a diffusion channel, but could be considered for studying the diffusion anisotropy [11,14,16]. Figure 1(b) shows a 2 × 2 × 2 βLG lattice.…”

Section: Calculationsmentioning

confidence: 99%

Diffusion of water and sodium counter-ions in nanopores of a β-lactoglobulin crystal: a molecular dynamics study

Malek¹,

Odijk²,

Coppens³

2005

Nanotechnology

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The dynamics of water and sodium counter-ions (Na + ) in a C222 1 orthorhombic β-lactoglobulin crystal is investigated by means of 5 ns molecular dynamics simulations. The effect of the fluctuation of the protein atoms on the motion of water and sodium ions is studied by comparing simulations in a rigid and in a flexible lattice. The electrostatic interactions of sodium ions with the positively charged LYS residues inside the crystal channels significantly influence the ionic motion. According to our results, water molecules close to the protein surface undergo an anomalous diffusive motion. On the other hand, the motion of water molecules further away from the protein surface is normal diffusive. Protein fluctuations affect the diffusion constant of water, which increases from 0.646 ± 0.108 to 0.887 ± 0.41 nm 2 ns −1 , when protein fluctuations are taken into account. The pore size (0.63-1.05 nm) and the water diffusivities are in good agreement with previous experimental results. The dynamics of sodium ions is disordered. LYS residues inside the pore are the main obstacles to the motion of sodium ions. However, the simulation time is still too short for providing a precise description of anomalous diffusion of sodium ions. The results are not only of interest for studying ion and water transport through biological nanopores, but may also elucidate water-protein and ion-protein interactions in protein crystals.

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Permeability of lysozyme tetragonal crystals to water

Cited by 34 publications

References 17 publications

Dynamic response of tetragonal lysozyme crystals to changes in relative humidity: implications for post-growth crystal treatments

Dynamic response of tetragonal lysozyme crystals to changes in relative humidity: implications for post-growth crystal treatments

The state diagram for cell adhesion under flow: Leukocyte rolling and firm adhesion

Diffusion of water and sodium counter-ions in nanopores of a β-lactoglobulin crystal: a molecular dynamics study

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