Vibrational dynamics of water molecules confined within trehalose H-bond imposed networks : A Raman response (original) (raw)
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Carbohydrate Research, 2005
A comparative investigation of trehalose, sucrose, and maltose in water solution has been performed using Raman scattering experiments and Molecular Dynamics simulations. From the analysis of the O-H stretching region in the [2500, 4000] cm À1 Raman spectral range, which includes for the first time the contribution of ÔfreeÕ water, and the statistical distribution of water HB probabilities from MD simulations, this study confirms the privileged interaction of trehalose with water above a peculiar threshold weight concentration of about 30%. The role of the hydration number of sugars-found higher for trehalose-on the destructuring effect of the water hydrogen bond network is also addressed. The analysis of the water O-H-O bending spectral range [1500, 1800] cm À1 reveals a change of the homogeneity of water molecules influenced by sugars, but the three investigated sugars are found to behave similarly.
Static and Dynamic Study of Disaccharides Trehalose, Maltose and Sucrose
Structural Chemistry, 2016
In this work, electronic structure calculations and Molecular Dynamics (MD) simulations were performed in order to carry out a static and dynamic study of disaccharides, trehalose, sucrose and maltose. These three disaccharides share the same chemical formula and the same number of OH groups; however, it has been widely shown that trehalose has a superior ability to protect biological structures. In order to contribute to the understanding of the factors that determine this ability of trehalose, in this work a comparative study of the three disaccharides in gas phase and dilute aqueous solution is performed. A detailed analysis of hydrogen bonds (HBs) was carried out using Quantum Theory of Atoms In Molecules (QTAIM) on wave functions obtained at B3LYP/ 6-311++G** level. Besides, stereoelectronic effects were examined by Natural Bond Orbital (NBO) analysis. In addition, the intra-and intermolecular HB interactions in MD runs of infinitely dilute aqueous solution of sugars have been monitored. Results show that the three disaccharides form a significant number of HBs of C-H•••O type, mainly in trehalose. An intermolecular bond of this type determines the conformational rigidity of trehalose in solution which contributes to stabilize a clam shell conformation as the one observed in the crystal. In this disaccharide, hydrogen bonds are more labile, showing a quickly exchange of the water molecules that form these HBs. This fact slows down ice formation and could be the explanation for trehalose capabilities as a cryoprotectant.
Water Dynamics and Structural Relaxation in Concentrated Sugar Solutions
Food Biophysics, 2013
The collective dynamics of concentrated aqueous solutions of the three well-known homologous disaccharides, namely, maltose, sucrose and trehalose, have been studied in an unexplored frequency region by Brillouin ultraviolet light scattering, as a function of temperature and concentration. In trehalose solutions, for water concentrations close to the sugar hydration number, the structural relaxation time above the freezing point of water proves to be 10 % smaller than in maltose/sucrose solutions, presaging a different reorganisation of the sugar matrix. This effect could help in reducing both desiccation stresses and ice formation in anhydrobiotic organisms. The relevance of this behaviour in bioprotection is briefly discussed.
Slowing down of water dynamics in disaccharide aqueous solutions
Journal of Non-Crystalline Solids, 2011
The dynamics of water in aqueous solutions of three homologous disaccharides, namely trehalose, maltose and sucrose, has been analyzed by means of molecular dynamics simulations in the 0-66 wt % concentration range. The low-frequency vibrational densities of states (VDOS) of water were compared with the susceptibilities χ" of 0-40 wt % solutions of trehalose in D 2 O obtained from complementary Raman scattering experiments. Both reveal that sugars significantly stiffen the local environments experienced by water. Accordingly, its translational diffusion coefficient decreases when the sugar concentration increases, as a result of an increase of water-water hydrogen bonds lifetimes and of the corresponding activation energies. This induced slowing down of water dynamics, ascribed to the numerous hydrogen bonds that sugars form with water, is strongly amplified at concentrations above 40 wt % by the percolation of the hydrogen bond network of sugars, and may partially explain their well-known stabilizing effect on proteins in aqueous solutions.
Slow dynamics of supercooled trehalose hydration water in comparison with bulk water
2020
Trehalose aqueous solutions are relevant in many technological applications, for example in cryopreservation of biomolecules. It is known that the presence of this disaccharide is able to slow down the dynamics of nearby water molecules and to modify their spatial rearrangement, nevertheless, a complete understanding of the properties of water-trehalose solutions and of trehalose cryoprotective properties is still lacking. Here we discuss recent molecular dynamics simulation results of water-trehalose solutions, performed at different temperatures upon cooling, and we compare the results with the behavior of the bulk phase. In particular we focus on the dynamical properties of hydration water, i.e., the water molecules in the hydration shell of the disaccharide. Hydration water shows a sub-diffusive behavior with respect to bulk water, the same structural relaxation typical of glass formers liquids, albeit slightly slower than in the bulk, and an additional relaxation process at lon...
Molecular Dynamics Studies of the Hydration of α,α-Trehalose
Journal of the American Chemical Society, 1997
Molecular dynamics simulations have been used to model the aqueous solvation of the nonreducing sugar R,R-trehalose. The anisotropic structuring of water around the trehalose molecule was calculated in a Cartesian coordinate frame fixed with respect to the sugar molecule by averaging water positions over the trajectories and was plotted in two and three dimensions relative to the sugar. The hydrogen bonding of this sugar to solvent was calculated and compared to other sugar solutes. Hydration was required to produce the experimental conformation, through the exchange of an internal hydrogen bond for similar bonds to solvent. This equilibrium conformation was found to impose extensive structuring on the adjacent solvent, with structuring extending out to at least the third "solvation shell", while pure liquid water exhibits such structure only in its nearest neighbors. The details of the structuring are determined by both the specific stereochemical topology of the molecule and its conformation, with considerable interplay between conformation and solvent structure. The effect of solute flexibility on the application of this solvent density mapping technique was also examined. While the extensive solvent structural perturbation induced by the solute suggests why the sugars in general are useful antidessicants and cryoprotectants, trehalose does not appear from these results to be unique in its solvation properties. In addition, the results are consistent with the suggestion that much of the effectiveness of trehalose could result from its direct binding to biological membranes and proteins rather than from unique solution properties.
Journal of Pharmaceutical Sciences, 2013
Raman investigations were performed in situ during freeze-drying of two model proteins, lysozyme and chymotrypsinogen. The structures of proteins dissolved in 0-30 wt % solutions of trehalose in D 2 O were monitored with the fingerprint (800-1800 cm −1 ) spectrum, simultaneously with freezing, ice sublimation, and water desorption analyzed in the O-D stretching (2200-2700 cm −1 ) region. In the absence of trehalose, the main changes were detected at the end of primary drying, and correspond to distortion and disordering of secondary structures. A stabilizing effect of trehalose was evidenced in primary and secondary drying stages. Raman images were calculated after freezing and primary drying, providing the distributions of trehalose, water, and protein which occur during the first two stages of the lyophilization cycle. Raman images show a slight heterogeneity in the degree of protein denaturation at the end of primary drying, in relation with the structure of the frozen product observed during freezing. The ability of trehalose to make the protein more rigid was determined as responsible for the protein stabilization during a lyophilization cycle.
Journal of Pharmaceutical Sciences
The bioprotective properties of 2 disaccharides (sucrose and trehalose) were analyzed during the freezedrying (FD) process and at the end of the process, to better understand the stabilization mechanisms of proteins in the solid state. In situ Raman investigations, performed during the FD process, have revealed that sucrose was more efficient than trehalose for preserving the secondary structure of lysozyme during FD, especially during the primary drying stage. The lower bioprotective effect of trehalose was interpreted as a consequence of a stronger affinity of this disaccharide to water, responsible for a severe phase separation phenomenon during the freezing stage. Dielectric spectroscopy investigations on the freezedried state of protein formulations have shown the capabilities of trehalose assisted by residual water to reduce the molecular mobility of the vitreous matrix, suggesting that trehalose is more efficient to preserve the protein structure during long-term storage.
Experimental study of the hydration properties of homologous disaccharides
Journal of biological physics, 2000
To get some insight into the hydration mechanisms of homologousdisaccharides, we report measurements on trehalose, maltose, and sucroseaqueous solutions. The interest on these systems is mainly due to theextraordinary properties of disaccharides and especially of trehalose, themost effective bio-protector against freezing and dehydration. To carry outthis study we have investigated the volumetric properties of the threedisaccharide solutions, by performing density and ultrasonic velocitymeasurements at different concentration and temperature values. Whatemerges from these studies is that trehalose shows, in comparison withmaltose and sucrose, the greatest structural sensitivity to temperaturechanges and the smallest values of the partial molar volume in all theinvestigated temperature range, this circumstance being indicative of a morepacked conformational arrangement.
Water–disaccharides interactions in saturated solution and the crystallisation conditions
Food Chemistry, 2008
This paper reports solubility data and measurements of viscosity of the saturated aqueous solutions of sucrose, maltitol, and trehalose. Likewise, the metastable zone width and velocity of nucleation of the three disaccharides are compared. The narrowest metastable zone is observed for maltitol and the largest for trehalose. Such behaviour is due to a higher affinity of trehalose for water. Moreover, the crystallisation of anhydrous disaccharides in aqueous solution necessitates that hydration water be removed and evacuated from crystal integration surface to the bulk of solution to allow the growth of crystals. This step of disassociation and diffusion of hydration water proves to be the controlling step of the crystallisation process. Structural features at the origin of the differences between the three sugars are studied by FTIR spectroscopy. Modifications of frequencies and intensities of the vibrations around the glycosidic bond are interpreted in terms of conformational flexibility. Arguments like H-bond strength or conformational flexibility of the two monomers around the glycosidic oxygen were evoked as possible explanations of the behaviour of disaccharides. Likewise stability of hydration of the disaccharides is derived from the interpretation of FTIR spectra. These structural features help in interpreting the differences in crystallisation conditions and to hypothesize about the cryoprotective ability of the studied molecules.