Structure of Aqueous Trehalose Solution by Neutron Diffraction and Structural Modeling

Abstract

The molecular structure of an aqueous solution of the disaccharide trehalose (CHO) has been studied by neutron diffraction and empirical potential structure refinement modeling. Six different isotope compositions with 33 wt % trehalose (corresponding to 38 water molecules per trehalose molecule) were measured to ensure that water-water, trehalose-water, and trehalose-trehalose correlations were accurately determined. In fact, this is the first neutron diffraction study of an aqueous trehalose solution in which also the nonexchangeable hydrogen atoms in trehalose are deuterated. With this approach, it was possible to determine that (1) there is a substantial hydrogen bonding between trehalose and water (∼11 hydrogen bonds per trehalose molecule), which is in contrast to previous neutron diffraction studies, and (2) there is no tendency of clustering of trehalose, in contrast to what is generally observed by molecular dynamics simulations and experimentally found for other disaccharides. Thus, the results give the structural picture that trehalose prefers to interact with water and participate in a hydrogen-bonded network. This strong network character of the solution might be one of the key reasons for its extraordinary stabilization effect on biological materials.

Structural Comparison between Sucrose and Trehalose in Aqueous Solution

“…Nonetheless, quantitative results are valuable to obtain to allow us to compare our findings to previous works, such as those in refs 1, 33, 34, and 41. Within the limits of the error bars, our hydration numbers of trehalose (Table S2) are consistent with these previous studies, 1,33,34,41 although our interpretation of the experimental results and models differs somewhat from those studies as further discussed below.…”

“…Although the fits capture most features of the experimentally obtained diffraction data and are in relatively good agreement (compared to e.g. previous mentioned studies on trehalose 1,33,34,41 ), there are still several discrepancies with the experimental data. These discrepancies are definitely larger than the experimentally measured differences between sucrose and trehalose.…”

“…The reference potential for the new trehalose EPSR model was set identical to our previous study. 1 Details regarding the force field parameters for the reference potential can be seen in Table S1 of the Supporting Information. The atomic labeling of sucrose was mainly set analogous to that of trehalose in ref 1 (see Figure 1) and ref 33; however, an additional oxygen type (O4) was defined for the hydroxymethyl groups on the fructose ring of the sucrose molecule.…”

Stabilization of proteins embedded in sugars and water as studied by dielectric spectroscopy

“…[22][23][24][25] It has also been shown that trehalose exhibits a stronger coupling of its dynamics to the dynamics of the proteins, compared to other disaccharides. 26,27 In order to study molecular dynamics of proteins and disaccharides in the presence of water, many different methods are commonly used, such as molecular dynamics simulations, 13,18,25 neutron scattering techniques, 19,22,[28][29][30][31][32][33][34][35][36][37][38][39] Raman-spectroscopy 17,[40][41][42][43] and many others. One particular method which has often been used, particularly for the purpose of studying disaccharides [44][45][46][47][48] and proteins, is dielectric spectroscopy.…”

Polymorphism in carbohydrate self-assembly at surfaces: STM imaging and theoretical modelling of trehalose on Cu(100)

“…Relating the molecular structure of trehalose to its conformations is extremely challenging. NMR, 6,7 X-ray 1 and neutron scattering 8,9 measurements have been performed to probe the trehalose-water interactions, in particular, which were complemented by numerical simulations. 1,5,10,11 Beyond that, the conformations and assembly motifs of saccharides in environments of reduced symmetry, e.g.…”