User Manual Privacy Policy Disclaimer Contact us
  Advanced SearchBrowse




Book Chapter

Cryoelectron Microscopy of Protein Crystals. Some Remarks on the Methodology


Zemlin,  Friedrich
Fritz Haber Institute, Max Planck Society;

External Ressource
No external resources are shared
Fulltext (public)
There are no public fulltexts stored in PuRe
Supplementary Material (public)
There is no public supplementary material available

Zemlin, F. (1990). Cryoelectron Microscopy of Protein Crystals. Some Remarks on the Methodology. In J. R. Fryer, & D. L. Dorset (Eds.), Electron Crystallography of Organic Molecules (pp. 305-308). Dordrecht: Springer.

Cite as: http://hdl.handle.net/21.11116/0000-0006-76E6-2
Cryoelectron microscopy is now proven to be an advantageous tool for structure research of protein crystals. Using a helium-cooled superconducting electron microscope, the following protein crystals have been imaged with high resolution in one projection: crotoxin complex 3.5 Â, purple membrane 2.8 Â, matrix porin OmpF 3.5 Â, surface protein of sulfolobus spec. B12 10 Â. Fine-structure details within the unit cell were resolved, although even at 4.5 K specimen temperature the crystal still suffers considerable radiation damage. While the tolerable dose is only 20 e/Â2, for atomic resolution a dose at least 100 times higher is needed. The ladder to these successes had two steps: First, the image was taken in a special way with a minimum of pre-exposure. Second, the low-dose images were evaluated by a sophisticated image-processing procedure, the main part of which is the cross-correlation averaging. The high resolution structure is in all cases revealed by averaging thousands of low-dose-imaged unit cells.