Single particle macromolecular structure determination via electron microscopy

Artificial Intelligence in Cryo-Electron Microscopy

Cryo-electron microscopy (cryo-EM) has become an unrivaled tool for determining the structure of macromolecular complexes. The biological function of macromolecular complexes is inextricably tied to the flexibility of these complexes. Single particle cryo-EM can reveal the conformational heterogeneity of a biochemically pure sample, leading to well-founded mechanistic hypotheses about the roles these complexes play in biology. However, the processing of increasingly large, complex datasets using traditional data processing strategies is exceedingly expensive in both user time and computational resources. Current innovations in data processing capitalize on artificial intelligence (AI) to improve the efficiency of data analysis and validation. Here, we review new tools that use AI to automate the data analysis steps of particle picking, 3D map reconstruction, and local resolution determination. We discuss how the application of AI moves the field forward, and what obstacles remain. We also introduce potential future applications of AI to use cryo-EM in understanding protein communities in cells.

Structural biology: a high-tech tool for biomedical research

PURPOSE OF REVIEW

Structural biology is one of the most informative disciplines available to biochemical research. It unites technologies that can reveal high-resolution (often atomic) details of the inner workings of biochemical systems. These insights are crucial for an understanding of basic life processes, such as the reaction mechanism of a drug-converting enzyme, signal transduction from one protein to another, activation of a metabolic pathway by a gene effector, action modes of drugs, or the consequences of a mutation on the function of an enzyme. Structural biology is also vital for characterizing the molecular basis of many diseases and often provides a starting platform for the development of specifically tuned therapies, for example by designing drugs that bind to particular targets in order to affect their functionality. An overview of the main techniques as well as some selected case studies are presented.

RECENT FINDINGS

Recent advances in the three major structure determination techniques (X-ray crystallography, nuclear magnetic resonance spectroscopy, and electron microscopy) have made it possible to obtain three-dimensional structural information on larger systems, at higher resolution and with much less effort than in the past. Because these techniques often provide complementary information, combining them is particularly powerful for gaining comprehensive insights into complex systems, as illustrated by the recent structure determinations of the low-density lipoprotein receptor and the ribosome.

SUMMARY

Structural biology is no longer exclusive to a few dedicated specialists. Many of its techniques are now easily accessible and can be used as tools in general life science research.