1. Structural Biology and Molecular Biophysics
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Measuring the optimal exposure for single particle cryo-EM using a 2.6 Å reconstruction of rotavirus VP6

  1. Timothy Grant
  2. Nikolaus Grigorieff  Is a corresponding author
  1. Janelia Research Campus, Howard Hughes Medical Institute, United States
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Cite this article as: eLife 2015;4:e06980 doi: 10.7554/eLife.06980

Abstract

Biological specimens suffer radiation damage when imaged in an electron microscope, ultimately limiting the attainable resolution. At a given resolution, an optimal exposure can be defined that maximizes the signal-to-noise ratio in the image. Using a 2.6 Å resolution single particle cryo-EM reconstruction of rotavirus VP6, determined from movies recorded with a total exposure of 100 electrons/Å2, we obtained accurate measurements of optimal exposure values over a wide range of resolutions. At low and intermediate resolutions our measured values are considerably higher than obtained previously for crystalline specimens, indicating that both images and movies should be collected with higher exposures than are generally used. We demonstrate a method of using our optimal exposure values to filter movie frames, yielding images with improved contrast that lead to higher resolution reconstructions. This 'high-exposure' technique should benefit cryo-EM work on all types of samples, especially those of relatively low molecular mass.

Article and author information

Author details

  1. Timothy Grant

    Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
    Competing interests
    The authors declare that no competing interests exist.
  2. Nikolaus Grigorieff

    Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, United States
    For correspondence
    niko@grigorieff.org
    Competing interests
    The authors declare that no competing interests exist.

Reviewing Editor

  1. Wesley I Sundquist, University of Utah School of Medicine, United States

Publication history

  1. Received: February 12, 2015
  2. Accepted: May 28, 2015
  3. Accepted Manuscript published: May 29, 2015 (version 1)
  4. Version of Record published: June 18, 2015 (version 2)

Copyright

© 2015, Grant & Grigorieff

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.

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