Refinement of atomic models in high resolution EM reconstructions using Flex-EM and local assessment.

ABSTRACT: As the resolutions of Three Dimensional Electron Microscopic reconstructions of biological macromolecules are being improved, there is a need for better fitting and refinement methods at high resolutions and robust approaches for model assessment. Flex-EM/MODELLER has been used for flexible fitting of atomic models in intermediate-to-low resolution density maps of different biological systems. Here, we demonstrate the suitability of the method to successfully refine structures at higher resolutions (2.5-4.5Å) using both simulated and experimental data, including a newly processed map of Apo-GroEL. A hierarchical refinement protocol was adopted where the rigid body definitions are relaxed and atom displacement steps are reduced progressively at successive stages of refinement. For the asses

SUBMITTER: Joseph AP 

PROVIDER: S-EPMC4854230 | biostudies-literature | 2016 May

REPOSITORIES: biostudies-literature