New insights into the interaction of proteins and disaccharides—The effect of pH and concentration

Abstract

To gain new insights into the interaction of proteins and disaccharides, we investigated the hydrodynamic radii, RhProt, of lysozyme molecules in solution and in a ternary protein-sugar-water system by PFG-NMR. Our approach is based on the assumption that the anhydrobiotic properties of disaccharides like trehalose are based on aggregation of sugar molecules to the proteins, i.e., accumulation of sugar molecules close to the protein, and that this process can be investigated by the experimentally detectable RhProt value of the protein. The R values are calculated from the experimentally determined diffusion coefficients and the application of a viscosity correction using the inert molecule dioxane as an internal viscosity reference. The experiments were performed as a function of sugar concentration, the overall particle concentration and the pH value. We investigated the disaccharides trehalose and sucrose, mainly for the reason that trehalose has well know cryptobiotic properties while sucrose, which is similar in size and structure, lacks these properties. The results show the formation of a protective sugar shell around the proteins over a wider range of concentrations and pH values in the case of trehalose.

Review of the current state of protein aggregation inhibition from a materials chemistry perspective: special focus on polymeric materials

“…One such condition is the solution pH, which affects protein aggregation by causing changes in protein conformation and stability. [124][125][126] Filipe et al showed that immunoglobulin G1 (IgG1) transformed from dimers to micrometer-sized aggregates in a few hours when the pH decreased from 6 to pH 1. 127 The pH can cause differences in the growth of the nucleus and the rate of aggregation 128 by influencing protein-protein interactions, 129,130 the solubility of protein aggregates, 131 and the reactivity of protein cross-linking reactions.…”

More than a Confinement: “Soft” and “Hard” Enzyme Entrapment Modulates Biological Catalyst Function

“…The analysis of solvent composition and HB patterns suggested that the sugar anchors a thin water layer at the protein surface, whose molecules bridge protein and matrix H-bond groups, reduce protein non-harmonic motions, and stabilize the protein conformation. Reducing the water content, a few direct protein-trehalose interactions start to emerge, indicating that the water replacement and water entrapment hypotheses are not mutually exclusive, but their occurrence depends only on external parameters, as hydration or sugar/protein ratio [163]. MD simulations showed also that trehalose could form patches around the protein, reducing the protein backbone flexibility [16,164].…”

Bioprotection Can Be Tuned with a Proper Protein/Saccharide Ratio: The Case of Solid Amorphous Matrices

“…This suggests that water replacement and water entrapment hypotheses are not mutually exclusive. Indeed, MD simulations show that trehalose could form patches around the protein, thereby reducing the flexibility of the protein backbone. , It has been observed that trehalose starts to form a protective coating at a high sugar/protein ratio …”

“…29,30 It has been observed that trehalose starts to form a protective coating at a high sugar/protein ratio. 31 The interactions between protein and matrix have been also studied on carboxy-myoglobin (MbCO) embedded in trehalose matrices at different residual hydrations, by Fourier transform infrared spectroscopy (FTIR). 32−34 In these studies, the CO stretching band (COB, ∼1900−2000 cm −1 ), one of the most studied protein spectroscopical markers, was used to account for the properties of the protein, 35,36 whereas the adjacent water association band (WAB, ∼2000−2400 cm −1 ) was employed for those of the matrix.…”