Abstract
A molecular dynamics simulation study concerning thermal stabilization of proteins by amorphous sugars was reviewed. First, a survey of several molecular simulations, especially molecular dynamics (MD) simulation, was described. Then the outlines of our experimental and MD simulation studies were reported as an example of studies on thermal stabilization of proteins by sugars. In the experimental study, thermal stability of enzymes in samples obtained by freeze drying of sugar-enzyme solutions was discussed. It was found that the thermal stabilizing effect of sugars was prominent when sugars were glassy state (amorphous) in samples. Focusing on a specific sugar, the thermal stabilizing effect was different depending on its crystallinity. As for MD simulation study related to the above experiment, it was found that thermal vibration of proteins was depressed more in case that sugars were amorphous than crystalline. The depression of vibration depended not only on the number of hydrogen bonds between sugars and the surface of protein, but also on the mean lifetime of those hydrogen bonds. It seems promising that molecular simulations, including MD simulation, will become more and more important tools which give us complemental information to experiments.
