In this proposal we will study the structure of the myoglobin-trehalose-water system. It is well known that trehalose has an excellent cryo- and bioprotective role for biomaterials, such as proteins. However, the exact mechanism of it is still widely debated, mainly because structural insights of the protein-trehalose-water system are lacking. Two main models have been proposed; the preferential hydration (or water entrapment) model, where water prefers to hydrogen bond to the protein surface, and the water replacement model, where the trehalose molecules display the water molecules at the protein surface. Our recent TGA measurements support the latter model, and we will now establish the correct structural model as well as to gain structural information of help to understand the dynamic results from a complementary IRIS experiment on the same system.