Contrast transfer function correction applied to cryo-electron tomography and sub-tomogram averaging

Zanetti, Giulia, Riches, James D., Fuller, Stephen D., & Briggs, John A. G. (2009) Contrast transfer function correction applied to cryo-electron tomography and sub-tomogram averaging. Journal of Structural Biology, 168(2), pp. 305-312.

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Abstract

Cryo-electron tomography together with averaging of sub-tomograms containing identical particles can reveal the structure of proteins or protein complexes in their native environment. The resolution of this technique is limited by the contrast transfer function (CTF) of the microscope. The CTF is not routinely corrected in cryo-electron tomography because of difficulties including CTF detection, due to the low signal to noise ratio, and CTF correction, since images are characterised by a spatially variant CTF. Here we simulate the effects of the CTF on the resolution of the final reconstruction, before and after CTF correction, and consider the effect of errors and approximations in defocus determination. We show that errors in defocus determination are well tolerated when correcting a series of tomograms collected at a range of defocus values. We apply methods for determining the CTF parameters in low signal to noise images of tilted specimens, for monitoring defocus changes using observed magnification changes, and for correcting the CTF prior to reconstruction. Using bacteriophage PRDI as a test sample, we demonstrate that this approach gives an improvement in the structure obtained by sub-tomogram averaging from cryo-electron tomograms.

Impact and interest:

40 citations in Scopus
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40 citations in Web of Science®

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ID Code: 74983
Item Type: Journal Article
Refereed: Yes
Keywords: Electron tomography, Image processing
DOI: 10.1016/j.jsb.2009.08.002
ISSN: 1047-8477
Subjects: Australian and New Zealand Standard Research Classification > BIOLOGICAL SCIENCES (060000) > BIOCHEMISTRY AND CELL BIOLOGY (060100) > Structural Biology (incl. Macromolecular Modelling) (060112)
Divisions: Current > Schools > School of Earth, Environmental & Biological Sciences
Current > Institutes > Institute for Future Environments
Current > QUT Faculties and Divisions > Science & Engineering Faculty
Deposited On: 12 Aug 2014 00:48
Last Modified: 14 Aug 2014 04:52

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