PMID: 32647824

Authors:

Wu M, Lander GC, Herzik MA Jr

Title:

Sub-2 Angstrom resolution structure determination using single-particle cryo-EM at 200keV.

Journal:

J Struct Biol X. 2020 Feb 28;4:100020. doi: 10.1016/j.yjsbx.2020.100020., eCollection 2020.

Abstract:

Although the advent of direct electron detectors (DEDs) and software developments have enabled the routine use of single-particle cryogenic electron microscopy (cryo-EM) for structure determination of well-behaved specimens to high-resolution, there nonetheless remains a discrepancy between the resolutions attained for biological specimens and the information limits of modern transmission electron microscopes (TEMs). Instruments operating at 300kV equipped with DEDs are the current paradigm for high-resolution single-particle cryo-EM, while 200kV TEMs remain comparatively underutilized for purposes beyond sample screening. Here, we expand upon our prior work and demonstrate that one such 200kV microscope, the Talos Arctica, equipped with a K2 DED is capable of determining structures of macromolecules to as high as approximately 1.7A resolution. At this resolution, ordered water molecules are readily assigned and holes in aromatic residues can be clearly distinguished in the reconstructions. This work emphasizes the utility of 200kV electrons for high-resolution single-particle cryo-EM and applications such as structure-based drug design.