CCP4 and PHENIX are popular packages to analyze the results of this technique. For 10 points each:
[10e] Name this technique used by Dorothy Hodgkin and Barbara Low to discover the structure of penicillin. In this technique, Bragg’s law is used to relate the angles and intensities of waves scattered from a lattice.
ANSWER: X-ray crystallography [or XRC; or X-ray diffraction or XRD; accept X-ray diffractometry; prompt on crystallography or diffraction]
[10m] X-ray crystallography is the most common technique used to create atomic coordinate files for this structural database. Users of this database download mmCIF files to study structures in visualization systems such as PyMOL.
ANSWER: Protein Data Bank [or PDB; accept Worldwide Protein Data Bank or wwPDB]
[10h] PDB structures are validated by MolProbity, which measures R-free, a set of three outliers, and this value. This quantity counts the number of times per 1,000 atoms that van der Waals radii overlap by 0.4 angstroms or more.
ANSWER: clashscore (The three outliers are Ramachandran, sidechain, and RSRZ outliers.)
<KP, Chemistry>