was discovered by chance about 150 years ago and was developed in the late 19th century as a powerful purification tool and as a demonstration of chemical purity
the crystallization of proteins, nucleic acids, and large biological complexes, such as viruses, depends on the creation of a solution that is supersaturated in the macromolecule but exhibits conditions that do not significantly perturb its natural state. Supersaturation is produced through the addition of mild precipitating agents such as neutral salts or polymers, and by the manipulation of various parameters that include temperature, ionic strength, and pH.
an important in the crystallization process are factors that can affect the structural state of the macromolecule, such as metal ions, inhibitors, cofactors, or other conventional small molecules
a variety of approaches have been developed that combine the spectrum of factors that affect and promote crystallization, and among the most widely used are:
vapor diffusion
dialysis
batch and liquid-liquid diffusion
successes in macromolecular crystallization have multiplied rapidly in recent years owing to the advent of practical, easy-to-use screening kits and the application of laboratory robotics