The precise knowledge of the structure of biological macromolecules forms the basis of understanding their function and their mechanism of action. It also lays the foundation for rational protein and drug design. The only method to obtain this knowledge is still crystallography. At present, the structures of about 400 proteins are known at or nearly at atomic proteins. However, only two of them are membrane proteins or complexes of the membrane proteins. The reasons for the difference is not the crystals of membrane proteins resists forming special problems when being analysed. The reason is...