About this Research Topic
3D electron crystallography methods are powerful for the determination of atomic molecular structures from micron- and nano-scale crystals. Several experimental implementations of electron diffraction, such as ADT, PEDT, RED and cRED, have been developed since 2007. These approaches, first applied to inorganic materials and organic small molecules, have now expanded greatly in scope and popularity. In 2014, MicroED emerged as a new tool for Cryo-EM, demonstrating that structures of protein macromolecules can be determined from protein nanocrystals by combining continuous rotation data collection and data processing using X-ray software. Modern implementations of 3D crystallography rely on standard transmission electron microscopes to collect electron diffraction patterns by continuously or periodically rotating single crystals. These approaches have recently broken new ground by resolving macromolecular structures at sub-angstrom resolution using direct methods, and allowing the atomic exploration of organic, beam-sensitive compounds at atomic scale from seemingly amorphous powders at rapid speeds. In its latest implementation, 3D electron crystallography has gone serial, it employs near parallel transmission electron beam to scan thousands of randomly orientated single crystals on EM grids in diffraction mode. These diffraction patterns are then processed for structure determination of crystalline materials as well as proteins at atomic resolution.
3D electron crystallography is a rapidly developing field with great opportunities for growths and applications. Therefore, we would like to propose four goals for this issue:
1. Specimen preparation for protein crystals – in particular for challenging samples such as membrane protein crystals and those of environment sensitive molecules. On this front, the application of focused ion beam has been revolutionary and allowed thinning of large protein crystals for MicroED. Further developments in this area are needed to improve specimen preparation;
2. Dynamic scattering has been a major concern for applying electron crystallography methods in material science. The accuracy of diffraction intensities are still worse than that in X-ray diffraction. Theoretical and experimental studies to address this fundamental problem will be the second focus of this issue;
3. Applications of 3D electron crystallography methods in structural biology, chemistry and material sciences through improvements in protocols, software and instrumentations will be a third, core topic of this issue; and lastly,
4. Developments and demonstrations of entirely new approaches in 3D electron crystallography will be covered.
Keywords: 3D Electron Crystallography, Protein, Small Molecules, High-resolution Structures
Important Note: All contributions to this Research Topic must be within the scope of the section and journal to which they are submitted, as defined in their mission statements. Frontiers reserves the right to guide an out-of-scope manuscript to a more suitable section or journal at any stage of peer review.