Pushing the resolution limit by correcting the Ewald sphere effect in single-particle Cryo-EM reconstructions

Dongjie Zhu; Xiangxi Wang; Qianglin Fang; James L Van Etten; Michael G Rossmann; Zihe Rao; Xinzheng Zhang

doi:10.1038/s41467-018-04051-9

Pushing the resolution limit by correcting the Ewald sphere effect in single-particle Cryo-EM reconstructions

Nat Commun. 2018 Apr 19;9(1):1552. doi: 10.1038/s41467-018-04051-9.

Authors

Dongjie Zhu^{1

2}, Xiangxi Wang¹, Qianglin Fang³, James L Van Etten⁴, Michael G Rossmann³, Zihe Rao^{1

5

6}, Xinzheng Zhang^{7

8

9}

Affiliations

¹ National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China.
² School of Life Science, University of Science and Technology of China, 230026, Hefei, China.
³ Department of Biological Sciences, Purdue University, 240 South Martin Jischke Drive, West Lafayette, IN, 47907-2032, USA.
⁴ Department of Plant Pathology and Nebraska Center for Virology, University of Nebraska, Lincoln, NE, 68583-0900, USA.
⁵ University of Chinese Academy of Sciences, 100049, Beijing, China.
⁶ Laboratory of Structural Biology, School of Medicine, Tsinghua University, 100084, Beijing, China.
⁷ National Laboratory of Biomacromolecules, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China. [email protected].
⁸ University of Chinese Academy of Sciences, 100049, Beijing, China. [email protected].
⁹ Center for Biological Imaging, CAS Center for Excellence in Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101, Beijing, China. [email protected].

Abstract

The Ewald sphere effect is generally neglected when using the Central Projection Theorem for cryo electron microscopy single-particle reconstructions. This can reduce the resolution of a reconstruction. Here we estimate the attainable resolution and report a "block-based" reconstruction method for extending the resolution limit. We find the Ewald sphere effect limits the resolution of large objects, especially large viruses. After processing two real datasets of large viruses, we show that our procedure can extend the resolution for both datasets and can accommodate the flexibility associated with large protein complexes.

Publication types

Research Support, Non-U.S. Gov't

Abstract

Publication types

Grants and funding