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@ARTICLE{Schrder:9741,
      author       = {Schröder, G.F. and Levitt, M. and Brunger, A.T.},
      title        = {{S}uper-resolution biomolecular crystallography with
                      low-resolution data},
      journal      = {Nature},
      volume       = {464},
      issn         = {0028-0836},
      address      = {London [u.a.]},
      publisher    = {Nature Publising Group},
      reportid     = {PreJuSER-9741},
      pages        = {1218 - 1222},
      year         = {2010},
      note         = {We thank P. D. Adams, S. C. Harrison and T. D. Fenn for
                      discussions. We also thank the National Science Foundation
                      for computing resources (CNS-0619926), the National
                      Institutes of Health for both Roadmap Grant PN2 (EY016525)
                      and grant GM63718 to M. L., and the Deutsche
                      Forschungsgemeinschaft (DFG) for support for G. F. S.},
      abstract     = {X-ray diffraction plays a pivotal role in the understanding
                      of biological systems by revealing atomic structures of
                      proteins, nucleic acids and their complexes, with much
                      recent interest in very large assemblies like the ribosome.
                      As crystals of such large assemblies often diffract weakly
                      (resolution worse than 4 A), we need methods that work at
                      such low resolution. In macromolecular assemblies, some of
                      the components may be known at high resolution, whereas
                      others are unknown: current refinement methods fail as they
                      require a high-resolution starting structure for the entire
                      complex. Determining the structure of such complexes, which
                      are often of key biological importance, should be possible
                      in principle as the number of independent diffraction
                      intensities at a resolution better than 5 A generally
                      exceeds the number of degrees of freedom. Here we introduce
                      a method that adds specific information from known
                      homologous structures but allows global and local
                      deformations of these homology models. Our approach uses the
                      observation that local protein structure tends to be
                      conserved as sequence and function evolve. Cross-validation
                      with R(free) (the free R-factor) determines the optimum
                      deformation and influence of the homology model. For test
                      cases at 3.5-5 A resolution with known structures at high
                      resolution, our method gives significant improvements over
                      conventional refinement in the model as monitored by
                      coordinate accuracy, the definition of secondary structure
                      and the quality of electron density maps. For re-refinements
                      of a representative set of 19 low-resolution crystal
                      structures from the Protein Data Bank, we find similar
                      improvements. Thus, a structure derived from low-resolution
                      diffraction data can have quality similar to a
                      high-resolution structure. Our method is applicable to the
                      study of weakly diffracting crystals using X-ray
                      micro-diffraction as well as data from new X-ray light
                      sources. Use of homology information is not restricted to
                      X-ray crystallography and cryo-electron microscopy: as
                      optical imaging advances to subnanometre resolution, it can
                      use similar tools.},
      keywords     = {Crystallization / Crystallography, X-Ray: methods /
                      Databases, Protein / Electrons / Likelihood Functions /
                      Models, Molecular / Oligopeptides: chemistry / Protein
                      Conformation / Software / Static Electricity / Oligopeptides
                      (NLM Chemicals) / J (WoSType)},
      cin          = {ISB-3},
      ddc          = {070},
      cid          = {I:(DE-Juel1)VDB942},
      pnm          = {Funktion und Dysfunktion des Nervensystems / BioSoft:
                      Makromolekulare Systeme und biologische
                      Informationsverarbeitung},
      pid          = {G:(DE-Juel1)FUEK409 / G:(DE-Juel1)FUEK505},
      shelfmark    = {Multidisciplinary Sciences},
      typ          = {PUB:(DE-HGF)16},
      pubmed       = {pmid:20376006},
      pmc          = {pmc:PMC2859093},
      UT           = {WOS:000276891100043},
      doi          = {10.1038/nature08892},
      url          = {https://juser.fz-juelich.de/record/9741},
}