title: Finding non-crystallographic symmetry in density maps of macromolecular structures.
abstract: The internal symmetry of a macromolecule is both an important aspect of its function and a useful feature in obtaining a structure by X-ray crystallography and other techniques. A method is presented for finding internal symmetry and other non-crystallographic symmetry in a structure based on patterns of density in a density map for that structure. Regions in map that are similar are identified by cutting out a sphere of density from a region that has high local variation and using an FFT-based correlation search to find other regions that match. The relationships among correlated regions are then refined to maximize their correlations and are found to accurately represent non-crystallographic symmetry in the map.
authors.affiliation: Los Alamos National Laboratory, Bioscience Division, Los Alamos, NM 87545, USA. terwilliger@lanl.gov
authors.forename: Thomas C
authors.initials: TC
authors.lastname: Terwilliger
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000648:ultrastructure*; D018360:Crystallography, X-Ray / Q000379:methods*; D046911:Macromolecular Substances / Q000737:chemistry / Q000648:ultrastructure; D008958:Models, Molecular; D046912:Multiprotein Complexes / Q000737:chemistry / Q000648:ultrastructure*; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D046911:Macromolecular Substances; D046912:Multiprotein Complexes; C030069:spore-specific proteins, Bacillus