Core/facility: Yale CryoEM Resource

About cryoEM

Jump to The basics — CryoEM discussion forums — Recommended reading — The debate on "resolution" — Workshops, online courses, and seminar recordings

The basics

Cryo-electron microscopy (cryoEM) is a powerful technique for studying the structures of biological samples that are rapidly frozen (vitrified) at liquid nitrogen temperatures.

It encompasses a range of applications, including single-particle analysis (SPA), cryo-electron tomography (cryoET), 2D electron crystallography, and microcrystal electron diffraction (microED).

Single particle analysis of purified protein complexes

Cheng Y, Grigorieff N, Penczek PA & Walz, T. A primer to single-particle cryo-electron microscopy. Cell. 2015, 161: 438–449.

Diagram comparing low- and high-res sample refinement

Cryo electron tomography

Lučič V, Rigort A, Baumeister W. Cryo-electron tomography: the challenge of doing structural biology in situ. J Cell Biol. 2013, 202: 407–419.

Diagram showing vitrification, thinning, electron tomography, and data analysis

MicroED

Nannenga BL and Gonen T. The cryo-EM method microcrystal electron diffraction (MicroED). Nature Methods. 2019, 16: 369–379.

$5-panel illustration of microcrystal electron diffraction$

CryoEM discussion forums

Cryo-EM scientists use a number of discussion forums to ask for advice and share knowledge. Here is an incomplete list.

The debate on "resolution"

Resolution in cryoEM is not based on the direct observation of the raw data. The numerical value highly depends on the data processing methods. The most commonly used criterion, Fourier shell correlation (FSC), reflects the self-consistency of the data, not the actual quality of the EM density map. The bottom line is never taking the FSC at face value. A resolution claim has to be backed by visual inspection of the density map and comparison with other structures solved at similar resolutions.

In-depth reading: