scholarly journals High-resolution structure determination of sub-100 kilodalton complexes using conventional cryo-EM

2018 ◽  
Author(s):  
Mark A. Herzik ◽  
Mengyu Wu ◽  
Gabriel C. Lander
Keyword(s):  
High Resolution ◽  
Structure Determination ◽  
Drug Target ◽  
Phase Plate ◽  
Biological Macromolecules ◽  
Cryo Electron Microscopy ◽  
Transmission Electron ◽  
High Resolution Structure ◽  
Resolution Structure

Determining high-resolution structures of biological macromolecules with masses of less than 100 kilodaltons (kDa) has long been a goal of the cryo-electron microscopy (cryo-EM) community. While the Volta Phase Plate has enabled cryo-EM structure determination of biological specimens of this size range, use of this instrumentation is not yet fully automated and can present technical challenges. Here, we show that conventional defocus-based cryo-EM methodologies can be used to determine the high-resolution structures of specimens amassing less than 100 kDa using a transmission electron microscope operating at 200 keV coupled with a direct electron detector. Our ~2.9 Å structure of alcohol dehydrogenase (82 kDa) proves that bound ligands can be resolved with high fidelity, indicating that these methodologies can be used to investigate the molecular details of drug-target interactions. Our ~2.8 Å and ~3.2 Å resolution structures of methemoglobin demonstrate that distinct conformational states can be identified within a dataset for proteins as small as 64 kDa. Furthermore, we provide the first sub-nanometer cryo-EM structure of a protein smaller than 50 kDa.

scholarly journals Tricks of the trade used to accelerate high-resolution structure determination of membrane proteins

FEBS Letters ◽  
2010 ◽  
Vol 584 (12) ◽  
pp. 2539-2547 ◽  
Author(s):  
Yo Sonoda ◽  
Alex Cameron ◽  
Simon Newstead ◽  
Hiroshi Omote ◽  
Yoshinori Moriyama ◽  
...  
Keyword(s):  
High Resolution ◽  
Membrane Proteins ◽  
Structure Determination ◽  
High Resolution Structure ◽  
Resolution Structure

scholarly journals Devitrification reduces beam-induced movement in cryo-EM

IUCrJ ◽  
2021 ◽  
Vol 8 (2) ◽  
pp. 186-194
Author(s):  
Jan-Philip Wieferig ◽  
Deryck J. Mills ◽  
Werner Kühlbrandt
Keyword(s):  
High Resolution ◽  
Structure Determination ◽  
High Energy ◽  
Full Potential ◽  
High Energy Electrons ◽  
High Resolution Structure ◽  
Image Blurring ◽  
Particle Images ◽  
Resolution Structure

As cryo-EM approaches the physical resolution limits imposed by electron optics and radiation damage, it becomes increasingly urgent to address the issues that impede high-resolution structure determination of biological specimens. One of the persistent problems has been beam-induced movement, which occurs when the specimen is irradiated with high-energy electrons. Beam-induced movement results in image blurring and loss of high-resolution information. It is particularly severe for biological samples in unsupported thin films of vitreous water. By controlled devitrification of conventionally plunge-frozen samples, the suspended film of vitrified water was converted into cubic ice, a polycrystalline, mechanically stable solid. It is shown that compared with vitrified samples, devitrification reduces beam-induced movement in the first 5 e Å−2 of an exposure by a factor of ∼4, substantially enhancing the contribution of the initial, minimally damaged frames to a structure. A 3D apoferritin map reconstructed from the first frames of 20 000 particle images of devitrified samples resolved undamaged side chains. Devitrification of frozen-hydrated specimens helps to overcome beam-induced specimen motion in single-particle cryo-EM, as a further step towards realizing the full potential of cryo-EM for high-resolution structure determination.

scholarly journals Von der „Blobology“ zur atomaren Auflösung der Kryo-Elektronenmikroskopie

BIOspektrum ◽  
2020 ◽  
Vol 26 (7) ◽  
pp. 710-713
Author(s):  
Holger Stark
Keyword(s):  
Electron Microscopy ◽  
High Resolution ◽  
Structure Determination ◽  
Protein Complexes ◽  
Pharmaceutical Research ◽  
New Drugs ◽  
Cryo Electron Microscopy ◽  
High Resolution Structure ◽  
First Time

AbstractIt took almost a century to develop electron microscopy into a powerful method for high-resolution structure determination of proteins. Technical improvements in microscopy, detector technology, and image processing software contributed to the exponential growth of high-resolution structures of protein complexes determined by cryo-electron microscopy in recent years. We now succeeded in breaking another resolution barrier in cryo-electron microscopy and for the first time in achieving true atomic resolution, where single atoms in the protein can indeed be visualized individually. These improvements in cryo-EM indicate that the method will continue to gain importance, not only as a method for structure determination but also in the development of new drugs in pharmaceutical research.

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