CTF determination and correction in electron cryotomography

Ultramicroscopy. 2006 May;106(7):587-96. doi: 10.1016/j.ultramic.2006.02.004. Epub 2006 Mar 23.

Abstract

Electron cryotomography (cryoET) has the potential to elucidate the structure of complex biological specimens at molecular resolution but technical and computational improvements are still needed. This work addresses the determination and correction of the contrast transfer function (CTF) of the electron microscope in cryoET. Our approach to CTF detection and defocus determination depends on strip-based periodogram averaging, extended throughout the tilt series to overcome the low contrast conditions found in cryoET. A method for CTF correction that deals with the defocus gradient in images of tilted specimens is also proposed. These approaches to CTF determination and correction have been applied here to several examples of cryoET of pleomorphic specimens and of single particles. CTF correction is essential for improving the resolution, particularly in those studies that combine cryoET with single particle averaging techniques.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cryoelectron Microscopy* / methods
  • Hepatitis B virus / ultrastructure
  • Imaging, Three-Dimensional / methods*
  • Radiographic Image Enhancement / methods*
  • Tomography* / methods