ABSTRACT
The term crystallization describes the process of crystal formation and its subsequent growth. Deliberate, methodical attempts at crystallizing macromolecules for the purpose of structure determination began in Cambridge in the 1950s and continue to the present day. The protein database (PDB) archive holds three-dimensional structures of proteins and other biological macromolecules. Three-dimensional structure determination is essential to understanding protein function. One fundamental assumption made about protein crystals is that the structure of the protein in the crystal is comparable to the one in solution. Crystal structures do sometimes depict artifacts, such as more flexible loops adopting strange conformations due to biologically irrelevant crystal contacts. During crystal formation, supersaturation needs to be reached, followed subsequently by slow precipitation of protein molecules. Vapor diffusion is the most commonly used method for protein crystallization. The plates for hanging drop vapor diffusion have to be greased along the rim of each well with vacuum grease.
