X-ray crystallography

X-ray crystallography determines the atomic and molecular arrangement in a crystal by measuring how its regularly spaced atoms diffract X-rays.

Bragg's law: A relation connecting X-ray wavelength, crystal-plane spacing, and the angles at which diffraction occurs. It predicts where crystal planes produce diffraction peaks.
Crystal lattice: An infinite periodic arrangement of points representing the translational symmetry of a crystal. The lattice’s periodicity creates the regular diffraction pattern used in structure determination.
Protein crystallography: The determination of protein structures from X-ray diffraction by protein crystals. It extends crystallographic methods to large, biologically important molecules.
Cryogenic electron microscopy: A method that images rapidly frozen specimens with an electron beam to determine molecular structures. It can determine many macromolecular structures without growing crystals.
Max von Laue: A German physicist who discovered X-ray diffraction by crystals in 1912. His discovery established that crystals diffract X-rays and X-rays have wave-like properties.
X-ray diffraction: The scattering of X-rays by matter, producing interference patterns that reveal structural order. Crystallography is a structural application of this broader scattering phenomenon.
Unit cell: The smallest repeating volume that, translated through space, generates a crystal lattice. Its dimensions and symmetry define the repeating structural unit measured by diffraction.
Myoglobin: An oxygen-binding protein whose structure was the first protein structure solved by X-ray crystallography. Its structure demonstrated that diffraction could reveal a protein’s three-dimensional fold.
Nuclear magnetic resonance spectroscopy: A spectroscopy method that uses nuclear spin behavior in magnetic fields to probe molecular structure and dynamics. It can study molecules in solution, unlike methods requiring an ordered crystal.
William Henry Bragg: A British physicist who developed X-ray spectrometry and early methods for analyzing crystal structures. He helped turn diffraction observations into a practical structural method.

Linked from 105 pages