Model-based local density sharpening of cryo-EM maps

• Published in: eLife Vol. 6
• Main Authors: Jakobi, Arjen J, Wilmanns, Matthias, Sachse, Carsten
• Format: Journal Article
• Language: English
• Published: England eLife Science Publications, Ltd 23.10.2017; eLife Sciences Publications Ltd; eLife Sciences Publications, Ltd
• Subjects: amplitude scaling; B-factor sharpening; Capsaicin receptors; Chemical models; Chemical research; contrast improvement; cryo-EM; Cryoelectron microscopy; Cryoelectron Microscopy - methods; Crystallography; DNA-directed RNA polymerase; Fourier transforms; Image processing; Image Processing, Computer-Assisted - methods; Laboratories; Methods; model building; Models, Molecular; Molecular biology; Noise; Proteasomes; RNA; Scaling; Secretase; Structural Biology and Molecular Biophysics; Symmetry; Tools and Resources; β-Galactosidase; Germany; B-factor sharpening; model building; structural biology; amplitude scaling; biophysics; cryo-EM; contrast improvement
• ISSN: 2050-084X; 2050-084X
• DOI: 10.7554/elife.27131

Atomic models based on high-resolution density maps are the ultimate result of the cryo-EM structure determination process. Here, we introduce a general procedure for local sharpening of cryo-EM density maps based on prior knowledge of an atomic reference structure. The procedure optimizes contrast of cryo-EM densities by amplitude scaling against the radially averaged local falloff estimated from a windowed reference model. By testing the procedure using six cryo-EM structures of TRPV1, β-galactosidase, γ-secretase, ribosome-EF-Tu complex, 20S proteasome and RNA polymerase III, we illustrate how local sharpening can increase interpretability of density maps in particular in cases of resolution variation and facilitates model building and atomic model refinement.