ABSTRACT
A description of the methodology of X-ray crystallography is beyond the scope of this book, but is covered in excellent reviews and monographs (Drenth 2006). X-ray crystallography can determine the arrangement of atoms in a protein by recording the intensity and pattern of the X-ray scattered by the electrons within the protein crystal. Diffraction appears as a pattern of regularly spaced spots known as reflections, from which the three-dimensional model of electron density can be recovered by using the Fourier transforms. The positions of the atomic nuclei are deduced from this electron density in a manner consistent with the covalent structure (sequence) of the protein.
