21 Apr Crystallography 101
Crystallography is about symmetry in nature. Art can be crystallographic. Humans are crystallographic. Look at a sunflower’s pattern and symmetry, it is crystallographic. Crystallography at the atomic and subatomic levels aids scientists to better understand how certain molecular structures are set up and how they interact in order to provide knowledge to create new classes and orders of drugs, for instance. X-ray crystallography gives scientists an accurate method to study those phase structures by amplifying crystal waves and diffracting them so that the atomic model structures can be refined and used for study.
What is X-ray Crystallography?
X-ray crystallography is an experimental technique resulting in a very accurate molecular structure determined by wavelengths scattered by the electron cloud of an atom of similar size. This is called diffraction. Once the electron cloud is diffused and the x-ray diffraction pattern is established, then the resulting electron density is calculated, and crystallographic phase information is collected. A model is then constructed against the refined data of the technique resulting in the molecular structure.
Rational drug design, and the ensuing development of therapeutic agents and drugs, are results of knowing these accurate molecular structures. X-ray crystallography does not have the size limitations of the spectroscopic NMR method. It answers specific questions regarding global fold structure and the details of atomic bonding. By looking at 2D and 3D renderings of molecular structure, scientists can ascertain how macromolecules interact and with whom they interact, how enzymatic reactions are catalyzed, and the reaction of drugs. By understanding disease at the molecular, or atomic, level, scientists can better develop new drugs to help people.
Once the crystallographer has found his good crystal or crystals, one single diffraction test is all that has to be undertaken. The main problem is growing the right crystal for the experiment. X-ray crystallography appears to agree well with NMR and general x-ray structures. It is able to be more highly refined for greater study. Greater study leads to greater discovery.