Atomic Resolution X-Ray Crystallography

**Semantic type:** Laboratory Procedure

**Definition:** A method of crystallography for the elucidation of protein structure with ultra-high resolution (< 1.2 Angstrom). X-rays are passed through crystals and the subsequent diffraction pattern is analyzed. The position of the atoms can be reconstructed using computerized analysis of the diffraction pattern. The atomic positions are accurately defined and fine details in the electron density become visible, which reveal small but significant structural changes.