title: Uniqueness of the macromolecular crystallographic phase problem.
abstract: Uniqueness of the phase problem in macromolecular crystallography, and its relationship to the case of single particle imaging, is considered. The crystallographic problem is characterized by a constraint ratio that depends only on the size and symmetry of the molecule and the unit cell. The results are used to evaluate the effect of various real-space constraints. The case of an unknown molecular envelope is considered in detail. The results indicate the quite wide circumstances under which ab initio phasing should be possible.
authors.affiliation: Computational Imaging Group, Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, New Zealand.
authors.forename: Rick P
authors.initials: RP
authors.lastname: Millane
authors.affiliation: Computational Imaging Group, Department of Electrical and Computer Engineering, University of Canterbury, Christchurch, New Zealand.
authors.forename: Romain D
authors.initials: RD
authors.lastname: Arnal
mesh_terms: D018360:Crystallography, X-Ray / Q000379:methods*; D046911:Macromolecular Substances / Q000032:analysis / Q000737:chemistry*; D008958:Models, Molecular; D044367:Phase Transition; D011487:Protein Conformation; D011506:Proteins / Q000032:analysis / Q000737:chemistry*; D012984:Software
chemical_list: D046911:Macromolecular Substances; D011506:Proteins
keywords: ab initio phasing; macromolecular crystallography; phase problem; uniqueness