Biological Crystallography (BX, MX, PX) is a technique used to determine the 3-dimensional structures of biological molecules such as proteins, viruses and nucleic acids (RNA and DNA) to a resolution higher than ~5 Angstrom. From the studies of this structural information, the detailed mechanism of the biological functions carried out by those macromolecules in living cells and organisms can be elucidated. The x-rays deflected ("scattered") by a single crystal of biological molecules concentrate into sharp intense spots (crystal diffraction pattern), and the structure of the biological molecule can be determined by analysis of the intensities and positions of the diffraction spots.