We study the structures of molecular assemblies using biochemical and biophysical techniques, and subsequently visualise them by electron cryomicroscopy (cryo-EM). By this technique, large macromolecular structures and multi-protein complexes can be studied in their near-native environment without the need for crystalisation. Small amounts of material are sufficient to obtain ‘snapshots’ of single particles in the electron cryomicroscope. The molecular images are combined by computer-aided image processing techniques to compute their 3D structures. As recent advances in hardware and software have led to a wave of atomic-resolution structures, cryo-EM shows great promise in becoming a routine tool for high-resolution structure determination of large macromolecules. To further realise the potential of the technique, the scientific community is still in great need of hardware-based improvements and software enhancements. Therefore, we are also interested in developing techniques, including sample preparation and data processing, to routinely achieve atomic-resolution structures by single-particle cryo-EM. For example, in our group we actively develop the software SPRING
for high-resolution cryo-EM structure determination of specimens with helical symmetry.