New insights into the interaction of proteins and disaccharides-The effect of pH and concentration.
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 Rhvalues 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.
Department of Physics, University of Halle, Halle, 06120, Germany.
Detlef
D
Reichert
Department of Physics, University of Halle, Halle, 06120, Germany.
Stefan
S
Gröger
Department of Physics, University of Halle, Halle, 06120, Germany.
Christiane
C
Hackel
D004058:Diffusion; D006863:Hydrogen-Ion Concentration; D009682:Magnetic Resonance Spectroscopy; D009113:Muramidase / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding; D013395:Sucrose / Q000737:chemistry / Q000378:metabolism*; D014199:Trehalose / Q000737:chemistry / Q000378:metabolism*; D014783:Viscosity
D013395:Sucrose; D014199:Trehalose; D009113:Muramidase
PFG-NMR; diffusion; disaccharide; protein; trehalose