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Title: Diamonds in the rough: a strong case for the inclusion of weak-intensity X-ray diffraction data

Here, new evidence is provided to show that the inclusion of weak-intensity, high-resolution X-ray diffraction data helps to improve the quality of experimental phases by imposing proper constraints on electron-density models during noncrystallographic symmetry averaging. Overwhelming evidence exists to show that the inclusion of weak-intensity, high-resolution X-ray diffraction data helps improve the refinement of atomic models by imposing strong constraints on individual and overall temperature B factors and thus the quality of crystal structures. Some researchers consider these data to be of little value and opt to discard them during data processing, particularly at medium and low resolution, at which individual B factors of atomic models cannot be refined. Here, new evidence is provided to show that the inclusion of these data helps to improve the quality of experimental phases by imposing proper constraints on electron-density models during noncrystallographic symmetry (NCS) averaging. Using electron-density correlation coefficients as criteria, the resolution of data has successfully been extended from 3.1 to 2.5 Å resolution with redundancy-independent merging R factors from below 100% to about 310%. It is further demonstrated that phase information can be fully extracted from observed amplitudes through de novo NCS averaging. Averaging starts with uniform density inside double-shelled sphericalmore » masks and NCS matrices that are derived from bound heavy-atom clusters at the vertices of cuboctahedrally symmetric protein particles.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Yale University, New Haven, CT 06520 (United States)
  2. The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States)
  3. (United States)
Publication Date:
OSTI Identifier:
22351320
Resource Type:
Journal Article
Resource Relation:
Journal Name: Acta Crystallographica. Section D: Biological Crystallography; Journal Volume: 70; Journal Issue: Pt 5; Other Information: PMCID: PMC4014128; PMID: 24816117; PUBLISHER-ID: dz5304; OAI: oai:pubmedcentral.nih.gov:4014128; Copyright (c) International Union of Crystallography 2014; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
Denmark
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; AMPLITUDES; ATOMS; CORRELATIONS; CRYSTAL STRUCTURE; DENSITY; DIAMONDS; ELECTRON DENSITY; INCLUSIONS; PROTEINS; R FACTORS; RESOLUTION; RESPIRATORS; SYMMETRY; X-RAY DIFFRACTION