title: Multiresolution phase extension of a trypsin inhibitor structure from 5 A to 2 A based on diffraction amplitudes alone.
abstract: For a specific structure of trypsin inhibitor, starting from a 5 A phase set, about 80% of the 2 A phases are correctly determined within an error of 18 degrees by applying a multiresolution refinement procedure. The refinement proceeds both in real and reciprocal spaces. In extending the structure from 5 to 2 A, the amplitudes of the reflections are the only requirements for this procedure. In contrast to the conventional phase extension scheme, the amplitudes are used not only in the Fourier synthesis but also in the real-space density modifications.
authors.affiliation: Department of Physics, University of Houston, Houston, Texas 77204, USA.
authors.forename: Xiangan
authors.initials: X
authors.lastname: Liu
authors.forename: Wu-Pei
authors.initials: WP
authors.lastname: Su
mesh_terms: D000465:Algorithms; D003198:Computer Simulation; D018360:Crystallography, X-Ray / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D044367:Phase Transition; D014361:Trypsin Inhibitors / Q000737:chemistry* / Q000648:ultrastructure*
chemical_list: D014361:Trypsin Inhibitors