title: CrystTwiV: a webserver for automated phase extension and refinement in X-ray crystallography.
abstract: An important stage in macromolecular crystallography is that of phase extension and refinement when initial phase estimates are available from isomorphous replacement or anomalous scattering or other methods. For this purpose, an alternative method called the twin variables (TwiV) method has been proposed. The algorithm is based on alternately transferring the phase information between the twin variable sets. The phase extension and refinement is evaluated with the crystallographic symmetry test by deliberately sacrificing the space-group symmetry in the starting set, then using its re-appearance as a criterion for correctness. Here we present a software program (CrysTwiV) that runs on the web (freely available at: http://btweb.aua.gr/crystwiv/) implementing the above-mentioned method.
authors.affiliation: Physics Lab, Department of Science, Agricultural University of Athens, 75 Iera Odos, Votanikos, Athens 118-55, Greece.
authors.forename: Trias
authors.initials: T
authors.lastname: Thireou
authors.forename: Vassilis
authors.initials: V
authors.lastname: Atlamazoglou
authors.forename: Manolis
authors.initials: M
authors.lastname: Levakis
authors.forename: Elias
authors.initials: E
authors.lastname: Eliopoulos
authors.forename: Athanassios
authors.initials: A
authors.lastname: Hountas
authors.forename: George
authors.initials: G
authors.lastname: Tsoucaris
authors.forename: Kostas
authors.initials: K
authors.lastname: Bethanis
mesh_terms: D000465:Algorithms; D001331:Automation; D019295:Computational Biology / Q000379:methods*; D018360:Crystallography, X-Ray / Q000379:methods*; D030562:Databases, Protein; D001330:Electronic Data Processing; D004583:Electrons; D020407:Internet; D046911:Macromolecular Substances; D015233:Models, Statistical; D008968:Molecular Conformation; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D012984:Software; D013816:Thermodynamics
chemical_list: D046911:Macromolecular Substances; D011506:Proteins