EXPERIMENTAL FIGURE 3-45 X-ray crystallography provides diffraction data from which the three-dimensional structure of a protein can be determined. (a) Basic components of an x-ray crystallographic determination. When a narrow beam of x-rays strikes a crystal, part of it passes straight through and the rest is scattered (diffracted) in various directions. The intensity of the diffracted waves, which form periodic arrangements of diffraction spots, is recorded on an x-ray film or with a solid-state electronic detector. (b) X-ray diffraction pattern for a protein crystal collected on a solid-state detector. From complex analyses of patterns of spots like this one, the locations of the atoms in a protein can be determined. See J. M. Berg, J. L. Tymoczko, G. J. Gatto, and L. Stryer, 2015, Biochemistry, 8th ed., Macmillan.

[Part (b) courtesy James M. Berger]