Several methods are currently used to determine the structure of a protein including X-ray crystallography, NMR spectroscopy and electron microscopy. In each of these methods the scientist uses many pieces of information to create the final atomic model. Primarily the scientist has some kind of experimental data about the structure of the molecule. For X-ray crystallography this is the X-ray diffraction pattern and for NMR spectroscopy it is information on the local conformation and distance between atoms that are close to one another. In electron microscopy it is an image of the overall shape of the molecule.