Structure determination of biological macromolecules using x-ray crystallography has been greatly improved in recent years through the development of a number of key technologies and better integration with sample preparation steps. This has enabled the crystallization of large numbers of proteins, including integral membrane proteins.Structure determination in crystallography refers to the process of elaborating the three-dimensional positional coordinates (and also, usually, the three-dimensional anisotropic displacement parameters) of the scattering centres in an ordered crystal lattice. Where a crystal is composed of a molecular compound, the term generally includes the three-dimensional description of the chemical structures of each molecular compound present.