Project description:A new era has begun for single particle cryo-electron microscopy (cryoEM) which can now compete with X-ray crystallography for determination of protein structures. The development of direct detectors constitutes a revolution that has led to a wave of near-atomic resolution cryoEM reconstructions. However, regardless of the sample studied, virtually all high-resolution reconstructions reported to date have been achieved using high-end microscopes. We demonstrate that the new generation of direct detectors coupled to a widely used mid-range electron microscope also enables obtaining cryoEM maps of sufficient quality for de novo modeling of protein structures of different sizes and symmetries. We provide an outline of the strategy used to achieve a 3.7 Å resolution reconstruction of Nudaurelia capensis ? virus and a 4.2 Å resolution reconstruction of the Thermoplasma acidophilum T20S proteasome.

| S-EPMC4497823 | biostudies-literature

1.8 A resolution structure of ?-galactosidase with a 200?kV CRYO ARM electron microscope.

Project description:We report the determination of the structure of Escherichia coli ?-galactosidase at a resolution of ?1.8?Å using data collected on a 200?kV CRYO ARM microscope equipped with a K3 direct electron detector. The data were collected in a single 24?h session by recording images from an array of 7 × 7 holes at each stage position using the automated data collection program SerialEM. In addition to the expected features such as holes in the densities of aromatic residues, the map also shows density bumps corresponding to the locations of hydrogen atoms. The hydrogen densities are useful in assigning absolute orientations for residues such as glutamine or asparagine by removing the uncertainty in the fitting of the amide groups, and are likely to be especially relevant in the context of structure-guided drug design. These findings validate the use of electron microscopes operating at 200?kV for imaging protein complexes at atomic resolution using cryo-EM.

| S-EPMC7340270 | biostudies-literature

2.6A b-Galactosidase Structure Solved Using an Indirect Scintillator-Coupled CMOS Detector at 300 kV

Project description: Not available

| EMPIAR-12033 | biostudies-other

1.8 Å resolution structure of β-galactosidase with a 200 kV CRYO ARM electron microscope

Project description: Not available

| EMPIAR-10446 | biostudies-other

Krios G4 apoferritin test with K3/BioQuantum SerialEM BIS 3x3x1

Project description: Not available

| EMPIAR-10559 | biostudies-other

Krios G4 apoferritin test with K3/BioQuantum SerialEM BIS 1x1x4

Project description: Not available