Three-dimensional electron cryo-microscopy as a powerful structural tool in molecular medicine

Area of Science:

• Structural biology
• Biophysics
• Microscopy

Background:

• Electron cryo-microscopy (cryo-EM) is essential for determining the structure of biological macromolecules and organelles.
• Cryo-EM requires specialized techniques for sample preservation, radiation damage mitigation, and signal enhancement.

Purpose of the Study:

• To provide a comprehensive introduction to three-dimensional electron cryo-microscopy (3D cryo-EM).
• To review various aspects of 3D cryo-EM, including sample preparation, data acquisition, and image reconstruction.

Main Methods:

• Discussion of sample preservation in a vacuum and strategies for minimizing radiation damage.
• Methods for improving the signal-to-noise ratio in electron micrographs of unstained specimens.
• Review of five major 3D reconstruction techniques: electron crystallography, helical reconstruction, icosahedral reconstruction, single-particle reconstruction, and electron tomography.

Main Results:

• Electron cryo-microscopy is uniquely capable of determining structures across a wide size range, from small proteins to organelles.
• The choice of reconstruction technique depends on the specimen type, with an emphasis on electron crystallography.
• Illustrative examples of medically relevant protein structures obtained using cryo-EM are presented.

Conclusions:

• 3D cryo-EM is a powerful and versatile tool for high-resolution structural biology.
• The presented review highlights the key methodologies and applications of 3D cryo-EM for structure determination.