Capturing the Dynamic Movement of Plant Macromolecules by Cryo-Electron Microscopy: Technical Details, First Uses in Photosynthetic Organisms, and Capability to Investigate Crop Physiology

Cryo-electron microscopy (Cryo-EM) is a key technique that allows the visualization of macromolecules in their near native state. Samples are frozen using vitreous ice at −170 °C, eliminating the need for crystallization, as would be required in X-ray crystallography or the use of fixatives in histological procedures. In this perspective paper, we explore the advantages of Cryo-EM over traditional techniques such as X-ray crystallography and nuclear magnetic resonance (NMR), highlighting its ability to capture the dynamics of molecular conformations, up to a limit of 52 KDa, such as viruses, membrane proteins, etc. This paper summarizes how Cryo-EM is changing the view of macromolecular structural biology, with special emphasis on understanding physiological processes common to bacteria, algae, model plants, and crops. It includes a historical perspective, a comparison of advantages (and disadvantages) with other, more classical, techniques, a detailed explanation of the technical details necessary to implement it, both the necessary parameters to be taken into account as well as possible problems, and some pioneer studies in crops as compared to similar studies performed in bacteria, algae, and model plants. In this respect, the most relevant applications for which the technique has been used in order to understand gene regulation, the interaction between membrane receptors and proteins, virus dynamics, and the ability to visualize the formation of self-assembly are described in more detail.