Solvent behaviour in flash-cooled protein crystals at cryogenic temperatures

Weik, Martin H.; Kryger, Gitay; Schreurs, Antoine M. M.; Bouma, BN; Silman, Israel; Sussman, Joel L.; Gros, Piet; Kroon, Jan

doi:10.1107/s0907444901001196

Cited by 70 publications

(102 citation statements)

References 34 publications

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“…This idea is experimentally supported by the fact that the length of the c axis remains invariant since the overpressure can be relieved in that direction without displacing protein molecules. This is in full agreement with the results reported by Weik et al (2001), who found that the volume expansion in trigonal TcAChE crystals is anisotropic; the cell axis along the solvent channels shows half of the relative expansion of the other cell axes. The existence of the channels also explains the in¯uence of the surface on the waiting time, since the larger the surface, the more channels are available.…”

Section: Figuresupporting

confidence: 82%

Soaking: the effect of osmotic shock on tetragonal lysozyme crystals

Lopéz-Jaramillo

Moraleda

González-Ramírez

et al. 2002

Acta Crystallogr D Biol Crystallogr

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Protein crystals crack when they are soaked in a solution with ionic strength suf®ciently different from the environment in which they grew. It is demonstrated for the case of tetragonal lysozyme that the forces involved and the mechanisms that lead to the formation of cracks are different for hypertonic and hypotonic soaking. Tetragonal lysozyme crystals are very sensitive to hypotonic shocks and, after a certain waiting time, cracks always appear with a characteristic pattern perpendicular to the crystallographic c axis. Conversely, a hypertonic shock is better withstood: cracks do not display any deterministic pattern, are only visible at higher differences in ionic strength and after a certain time a phenomenon of crystal reconstruction occurs and the cracks vanish. At the lattice level, the unit-cell volume expands in hypotonic shock and shrinks under hypertonic conditions. However, the compression of the unit cell is anisotropic: the c axis is compressed to a minimum, beyond which it expands despite the unit-cell volume continuing to shrink. This behaviour is a direct consequence of the positive charge that the crystals bear and the existence of channels along the crystallographic c axis. Both features are responsible for the Gibbs±Donnan effect which limits the free exchange of ions and affects the movement of water inside the channels and bound to the protein.

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Section: Figuresupporting

confidence: 82%

Soaking: the effect of osmotic shock on tetragonal lysozyme crystals

Lopéz-Jaramillo

Moraleda

González-Ramírez

et al. 2002

Acta Crystallogr D Biol Crystallogr

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“…It is difficult to deny the possibility that the cubic ice formation in the solvent channel induces small changes in protein conformations and increased fluctuation. This idea is supported by a report that cell expansions are observed in various protein crystals having large solvent channels, and that the magnitude of expansion correlates with solvent channel size (Weik et al 2001). …”

Section: Correlation Between the Internal Motions Of Protein And Hydrsupporting

confidence: 70%

Water–protein interactions from high–resolution protein crystallography

Nakasako

2004

Phil. Trans. R. Soc. Lond. B

164

119

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To understand the role of water in life at molecular and atomic levels, structures and interactions at the protein-water interface have been investigated by cryogenic X-ray crystallography. The method enabled a much clearer visualization of definite hydration sites on the protein surface than at ambient temperature. Using the structural models of proteins, including several hydration water molecules, the characteristics in hydration structures were systematically analysed for the amount, the interaction geometries between water molecules and proteins, and the local and global distribution of water molecules on the surface of proteins. The tetrahedral hydrogen-bond geometry of water molecules in bulk solvent was retained at the interface and enabled the extension of a three-dimensional chain connection of a hydrogen-bond network among hydration water molecules and polar protein atoms over the entire surface of proteins. Networks of hydrogen bonds were quite flexible to accommodate and/or to regulate the conformational changes of proteins such as domain motions. The present experimental results may have profound implications in the understanding of the physico-chemical principles governing the dynamics of proteins in an aqueous environment and a discussion of why water is essential to life at a molecular level.

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“…NMR studies of water adsorbed to porous glass show that 2.5-3 monolayers are essentially in a ''frozen'' amorphous structure even at room temperature, and that this fraction remains amorphous as the sample is cooled to freezing temperatures [27]. Water confined inside the 2 nm pores of porous glass does not crystallize [28], and it crystallizes only very slowly in the 6.5 nm channels of certain protein crystals [29].…”

Section: Prl 110 015703 (2013) P H Y S I C a L R E V I E W L E T T Ementioning

confidence: 99%

Critical Droplet Theory Explains the Glass Formability of Aqueous Solutions

2013

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When pure water is cooled at $10 6 K=s, it forms an amorphous solid (glass) instead of the more familiar crystalline phase. The presence of solutes can reduce this required (or ''critical'') cooling rate by orders of magnitude. Here, we present critical cooling rates for a variety of solutes as a function of concentration and a theoretical framework for understanding these rates. For all solutes tested, the critical cooling rate is an exponential function of concentration. The exponential's characteristic concentration for each solute correlates with the solute's Stokes radius. A modification of critical droplet theory relates the characteristic concentration to the solute radius and the critical nucleation radius of ice in pure water. This simple theory of ice nucleation and glass formability in aqueous solutions has consequences for general glass-forming systems, and in cryobiology, cloud physics, and climate modeling. DOI: 10.1103/PhysRevLett.110.015703 PACS numbers: 64.60.QÀ, 05.40.Àa, 64.70.dg Ice nucleation and growth are of major interest in fields ranging from cryobiology to atmospheric physics. Ice is a key issue in cryopreservation of cells and tissues [1] and in cryocooling of samples for macromolecular crystallography [2,3], where solutes like salts, sugars, alcohols, and polyols can have dramatic effects on ice formation. In atmospheric physics, models of cloud formation are sensitive to the nature of the critical nucleus of ice crystals [4] with implications for climate models [5]. Supercooled water is an interesting system in its own right [6], and the formation of crystalline phases from supercooled solutions is an active area of study [7].Previous experiments have focused on properties such as the melting and glass transition temperatures, and models to explain the data have largely been phenomenological. Similar models have been applied to explain glass formability in a wide variety ofnonaqueous systems. Here, we report measurements of the minimum cooling rates [or ''critical cooling rates'' (CCRs)] required to prevent ice formation in aqueous solutions during cooling to $100 K or below. We show that a surprisingly simple statistical modification to classical thermodynamic nucleation theory provides an excellent account of these data.We studied eight different solutes (see Fig. 1), including a salt (sodium chloride), simple alcohols (methanol, ethanol), sugars (dextrose, trehalose), polyols (glycerol, ethylene glycol), and polyethylene glycol 200 (PEG 200). All are compact and highly soluble and can have large effects on critical cooling rates required for vitrification.The effects of these solutes on ice nucleation were evaluated by measuring the critical cooling rate above which no ice was observed. Below the critical rate, a sample turns opaque on cooling, indicating the formation of polycrystalline ice. As the rate increases, a transition to transparent samples is observed. This optical transition corresponds to a transition in the x-ray diffraction patterns obtained from the cooled sam...

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Solvent behaviour in flash-cooled protein crystals at cryogenic temperatures

Cited by 70 publications

References 34 publications

Soaking: the effect of osmotic shock on tetragonal lysozyme crystals

Soaking: the effect of osmotic shock on tetragonal lysozyme crystals

Water–protein interactions from high–resolution protein crystallography

Critical Droplet Theory Explains the Glass Formability of Aqueous Solutions

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