%0 Journal Article
%A Brunger, A.T.
%A Adams, P.D.
%A Fromme, P.
%A Fromme, R.
%A Levitt, M.
%A Schröder, G.F.
%T Improving the accuracy of macromolecular structure refinement at 7 Å resolution
%J Structure
%V 20
%@ 0969-2126
%C London [u.a.]
%I Elsevier Science
%M PreJuSER-111909
%P 957 - 966
%D 2012
%Z Record converted from VDB: 16.11.2012
%X In X-ray crystallography, molecular replacement and subsequent refinement is challenging at low resolution. We compared refinement methods using synchrotron diffraction data of photosystem I at 7.4 Å resolution, starting from different initial models with increasing deviations from the known high-resolution structure. Standard refinement spoiled the initial models, moving them further away from the true structure and leading to high R(free)-values. In contrast, DEN refinement improved even the most distant starting model as judged by R(free), atomic root-mean-square differences to the true structure, significance of features not included in the initial model, and connectivity of electron density. The best protocol was DEN refinement with initial segmented rigid-body refinement. For the most distant initial model, the fraction of atoms within 2 Å of the true structure improved from 24% to 60%. We also found a significant correlation between R(free) values and the accuracy of the model, suggesting that R(free) is useful even at low resolution.
%K Bacterial Proteins: chemistry
%K Crystallography, X-Ray
%K Models, Molecular
%K Photosystem I Protein Complex: chemistry
%K Protein Structure, Secondary
%K Protein Structure, Tertiary
%K Software
%K Structural Homology, Protein
%K Bacterial Proteins (NLM Chemicals)
%K Photosystem I Protein Complex (NLM Chemicals)
%F PUB:(DE-HGF)16
%9 Journal Article
%$ pmid:22681901
%2 pmc:PMC3380535
%U <Go to ISI:>//WOS:000305094500004
%R 10.1016/j.str.2012.04.020
%U https://juser.fz-juelich.de/record/111909