PT  - JOURNAL ARTICLE
AU  - Mark A. Herzik, Jr.
AU  - Mengyu Wu
AU  - Gabriel C. Lander
TI  - Achieving better than 3 Å resolution by single particle cryo-EM at 200 keV
AID  - 10.1101/141994
DP  - 2017 Jan 01
TA  - bioRxiv
PG  - 141994
4099  - http://biorxiv.org/content/early/2017/05/25/141994.short
4100  - http://biorxiv.org/content/early/2017/05/25/141994.full
AB  - Technical and methodological advances in single-particle cryo-electron microscopy (cryo-EM) have expanded the technique into a resolution regime that was previously only attainable by X-ray crystallography. Although single-particle cryo-EM has proven to be a useful technique for determining the structures of biomedically relevant molecules at near-atomic resolution, nearly 98% of the structures resolved to better than 4 Å resolution have been determined using 300 keV transmission electron microscopes (TEMs). We demonstrate that it is possible to obtain cryo-EM reconstructions of macromolecular complexes at a range of sizes to better than 3 Å resolution using a 200 keV TEM. These structures are of sufficient quality to unambiguously assign amino acid rotameric conformations and identify ordered water molecules, features previously thought only to be resolvable using TEMs operating at 300 keV.