X-ray Crystallography

This is the most commonly used of the structural biology disciplines. Surprisingly, when proteins, DNA, RNA, or complexes of these macromolecules are forced to precipitate out of solution, sometimes the individual macromolecules orientate into an ordered repeating lattice, or crystal. The technique of X-ray crystallography relies on this ability to grow crystals of the protein (or macromolecule) of interest. This is because the ordered lattice of a crystal allows scattering of X-rays (diffraction), which the crystallographer measures and then manipulates by computer to discern the three-dimensional atomic-level structure of the protein or macromolecule.