Cryogenic Electron Microscopy (Cryo EM) is a technique used to study the structure and function of macromolecules with near atomic resolution. Structural biologists employ Cryo EM to identify and map individual atoms, in the pursuit of understanding how structure bestows function. In recent years, advancements in Cryo EM resolution have enabled researchers to study protein structure and molecular binding in unprecedented detail. Single particle Cryo EM in particular has emerged as a high throughput method of obtaining receptor-ligand interaction data, with enormous implications for drug discovery research.
Plasma cleaning plays an integral role in developing uniform Cryo EM samples and high-resolution images. By rendering grids hydrophilic, plasma enables aqueous samples to distribute evenly across the Cryo EM grid surfaces. Immediately following sample deposition, grids are flash frozen in liquid ethane or propane to form vitreous ice that embeds the sample macromolecule. As a result of plasma treatment, researchers can form vitreous ice layers that are tens of nanometers thick with even distribution. Plasma is used to treat copper, gold, or molybdenum holey Cryo EM grids with diverse mesh and hole sizes.
Cryo EM Articles
Cho H-J, Hyun J-K, Kim J-G, Jeong HS, Park HN, You D-J, and Jung HS. “Measurement of ice thickness on vitreous ice embedded cryo-EM grids: investigation of optimizing condition for visualizing macromolecules”. J. Anal. Sci. Technol. 2013 4: 7 10.1186/2093-3371-4-7
Huo J, Bas A. L, Ruza R. R, Duyvesteyn H. M. E, Mikolajek H, Malinauskas T, Tan T. K, Rijal P, Dumoux M, Ward P. N, Ren J, Zhou D, Harrison P. J, Weckener M, Clare D. K, Vogirala V. K, Radecke J, and Moynie L. “Neutralizing nanobodies bind SARS-CoV-2 spike RBD and block interaction with ACE2”. Nature Structural & Molecular Biology 2020 27: 846-854 10.1038/s41594-021-00566-w
Rachel R, Walther P, Maaßen C, Daberkow I, Matsuoka M and Witzgall R. “Dual-axis STEM tomography at 200 kV: Setup, performance, limitations”. Journal of Structural Biology 2020 211(3): 107551. 10.1016/j.jsb.2020.107551
Wang H, Yan X, Aigner H, Bracher A, Nguyen N, Hee W, Long B, Price G, Hartl F and Hayer-Hartl M. “Rubisco condensate formation by CcmM in β-carboxysome biogenesis”. Nature 2019, 566: 131-135 https://doi.org/10.1038/s41586-019-0880-5
Zhang Y, Li S, Zeng C, Huang G, Zhu X, Wang Q, Wang K, Zhou Q, Yan C, Zhang W, Yang G, Liu M, Tao Q, Lei J, and Shi Y. “Molecular architecture of the luminal ring of the Xenopus laevis nuclear pore complex”. Cell Research 2020 30: 532-540 https://doi.org/10.1038/s41422-020-0320-y
Zhao L, Xu J, Zhao W, Sung P, and Wang H-W. “Chapter Seven – Determining the RAD51-DNA Nucleoprotein Filament Structure and Function by Cryo-Electron Microscopy”. Methods Enzymol. 2018 600: 179-199 10.1016/bs.mie.2017.12.002