Chapter 19.9 Four-dimensional cryo-electron microscopy at quasi-atomic resolution: IMAGIC 4D
Crystallography of biological macromolecules
Second Online Edition (2012)
Part 19. Other experimental techniques
Published Online: 14 APR 2012
© International Union of Crystallography 2006
International Tables for Crystallography
How to Cite
van Heel, M., Portugal, R., Rohou, A., Linnemayr, C., Bebeacua, C., Schmidt, R., Grant, T. and Schatz, M. 2012. Four-dimensional cryo-electron microscopy at quasi-atomic resolution: IMAGIC 4D. International Tables for Crystallography. F:19:19.9:624–628.
- Published Online: 14 APR 2012
The traditional tools of the structural biologist seeking to understand macromolecules and their complexes are X-ray crystallography and NMR spectroscopy. Single-particle cryo-electron microscopy (cryo-EM) has established itself as a new structural-biology technique over the last 15 years. Spectacular insights into the functioning of macromolecular complexes have been achieved especially from combining cryo-EM with the earlier approaches. The resolution levels achieved improved over the last decade from ∼10 Å to sometimes better than ∼4 Å, meaning that a de novo structure determination based on single-particle cryo-EM studies alone is now feasible. More challenging is the new perspective that cryo-EM brings: sorting heterogeneous populations of molecules into individual three-dimensional conformers resulting in sequences of related three-dimensional structures, or in short ‘4D cryo-EM’. Thanks to these developments, single-particle cryo-EM has become the technique of choice for shedding light on the functioning of many a complex biological system. The design of the software instrumentation for 4D cryo-EM is crucial. In this chapter we elaborate on organization issues for single-particle cryo-EM software, as exemplified by recent developments in the IMAGIC 4D software system.
- cryo-electron microscopy;
- IMAGIC 4D