Improving the accuracy of macromolecular structure refinement at 7 A resolution.

ABSTRACT: 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 mos

SUBMITTER: Brunger AT 

PROVIDER: S-EPMC3380535 | biostudies-literature | 2012 Jun

REPOSITORIES: biostudies-literature