Zernike phase contrast cryo-electron microscopy and tomography for structure determination at nanometer and subnanometer resolutions

Structure. 2010 Aug 11;18(8):903-12. doi: 10.1016/j.str.2010.06.006.


Zernike phase contrast cryo-electron microscopy (ZPC-cryoEM) is an emerging technique that is capable of producing higher image contrast than conventional cryoEM. By combining this technique with advanced image processing methods, we achieved subnanometer resolution for two biological specimens: 2D bacteriorhodopsin crystal and epsilon15 bacteriophage. For an asymmetric reconstruction of epsilon15 bacteriophage, ZPC-cryoEM can reduce the required amount of data by a factor of approximately 3, compared with conventional cryoEM. The reconstruction was carried out to 13 A resolution without the need to correct the contrast transfer function. New structural features at the portal vertex of the epsilon15 bacteriophage are revealed in this reconstruction. Using ZPC cryo-electron tomography (ZPC-cryoET), a similar level of data reduction and higher resolution structures of epsilon15 bacteriophage can be obtained relative to conventional cryoET. These results show quantitatively the benefits of ZPC-cryoEM and ZPC-cryoET for structural determinations of macromolecular machines at nanometer and subnanometer resolutions.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Bacteriophages / ultrastructure
  • Bacteriorhodopsins / ultrastructure
  • Cryoelectron Microscopy / methods*
  • Crystallography / methods*
  • Electron Microscope Tomography / methods*
  • Epsilonproteobacteria / virology
  • Image Processing, Computer-Assisted / methods*
  • Microscopy, Phase-Contrast / methods*
  • Models, Molecular*


  • Bacteriorhodopsins