Two scientific groups reported on the establishment of cryoelectronic microscope, allowing measurements with a resolution of 1.2 angstroms. This permission gives you the opportunity to explore the work of biomolecules at the atomic level. Preprints available on the bioRxiv website (1, 2), briefly about these studies, describes in an editorial Nature.
Cryoelectron microscopy is a form of transmission electron microscopy, where the sample is studied at low temperatures. This approach allows a natural way to capture objects in contrast to x-ray crystallography, where the sample is artificially kristallizuetsya. In the study of the object by x-ray crystallography, the researchers can spend months and years to get to crystallize the studied structure, and many important from the medical point of view, the proteins do not form usable crystals. Read more about cryoelectron microscopy and its advantages you can read in our article “the Shadow in the ice”.
The main application cryoelectron microscopes lies in the study of organic structures. In 2017 the Nobel prize in chemistry was awarded to Jacques Dubose (Jacques Dubochet), Joachim Frank (Joachim Frank) and Richard Henderson (Richard Henderson) with the wording “for the development of cryoelectronic of high-resolution microscopy for structure determination of biomolecules in solution”. However, for the understanding of the biomolecules at the atomic level resolution of modern microscopes cryoelectronic need to improve.
On may 22 there were two independent Preprint on the biorXiv website (1, 2) from a group from Germany under the leadership of Holger stark (Holger Stark) and the group from England under the leadership of Stors Seresa (Sjors H. W. Scheres), which presented methods for determining three-dimensional structures of proteins by cryoelectronic microscope with resolution up to 1.25 and 1.2 Angstrom, respectively. This permission allows you to see the individual atoms in a protein recristallisation — for example, the radius of the hydrogen atom 0.5 angstroms, and the gold 1.7 Angstrom.
Both groups studied protein apoferritin. Group stark studied protein structure using the installation, which ensures that electrons emitted by the microscope are moved with the same speed before you get to the sample — this method greatly increases the resolution of the images. Group Sheresa used a similar technology to maintain a constant speed of electrons, moreover they applied post-processing methods that reduce noise from the reflected electrons.