CryoEM at IUCrJ: a new era

Since 2012, the advent of new electron detectors and improved computational programs together with substantial improvements in the electron microscopes themselves has produced an avalanche of new publications and coordinate depositions in the Electron Microscopy Data Bank (EMDB) and the Protein Data Bank (PDB). The productivity and power of the method has attracted many newcomers, from cell biologists who have a more biological emphasis, to those from adjacent disciplines such as crystallography and NMR spectroscopy who already have extensive depth of experience in structural biology. The recent successes span a wide range and include small proteins, as well as flexible and multi-domain protein complexes, several of which have proved to be resistant to analysis by X-ray crystallography over the years. Further, the level of automation in all aspects of the workflow has increased, making it easier for new users to adopt the method and to use it successfully.

A brief overview of advances in cryoEM can be found in Subramaniam et al. (2016). IUCrJ 3, 3-7; doi: 10.1107/S2052252515023738. An overview of the advances of cryoEM cannot be completed without mentioning the achievements and potential of electron cryotomography (cryoET). The application of cryoET to understand the macromolecular architectures of eukaryotic cells has shown that this method has enormous potential for investigating structures at the sub-cellular level. It is also possible to carry out sub-tomogram averaging in three dimensions to improve the resolution of structure determination of structures that are found in multiple copies in each tomogram. In principle, the averaging of sub-tomogram volumes should eventually produce maps at resolutions comparable to those produced using single particle cryoEM methods.

During the next few years, we expect that technical advances will make cryoEM more powerful and versatile than it is at present. We anticipate that further advances will occur in detector technology, phase plates, Cc correctors, computing power and algorithms, design of better specimen supports, and improved imaging strategies, although there are unsolved problems in each of these areas that might take a few years to overcome.

We hope that IUCrJ will be a key journal that can ride the wave of all the expected (and unexpected) technical advances that we believe will continue to make cryoEM methods even more powerful in the coming decade. The journal can act as a vehicle to publicise these advances and help the cryoEM field to move forward coherently. CryoEM itself may become the first choice method at the start of any structural biology project, since it requires a smaller quantity of material that is less pure, less stable and less homogeneous than needed for many other methods. It may even become the dominant method in structural biology in the future.

This article is a short extract reprinted from an article published in the journal IUCrJ