Direct detection pays off for electron cryo-microscopy

Abstract

Improved electron detectors and image-processing techniques will allow the structures of macromolecules to be determined from tens of thousands of single-particle cryo-EM images, rather than the hundreds of thousands needed previously.

Keywords: Bayesian; Direct electron detectors; Electron microscopy; Image processing; S. cerevisiae; T. thermophilus; ribosome.

Figure 1.. Electron micrograph of double-layered rotavirus particles frozen in a thin layer of amorphous ice.

The image was recorded by the author and co-workers using the DE-12 direct electron detector (Direct Electron, San Diego, United States) in movie mode at 40 frames per second. In panel A, 60 frames have been averaged without alignment, resulting in an image that is blurred due to beam-inducted movement. In panel B the frames have been aligned to compensate for this movement, which results in an image with significantly reduced blurring and improved contrast. The alignment method used here involved tracking the movement of the particles (Brilot et al., 2012); the alignment method used by Bai et al. used additional statistics to predict the movement of the particles caused by the electron beam. Scale bar = 50 nm.