The Nobel prize in chemistry this year was given to Jacques Dubose, Richard Henderson, and Joachim Frank for the development of a method of microscopy which allows us to see biomolecules as they are.


Nobel prize winners in chemistry of 2017, from left to right: Jacques Dubose, Joachim Frank, Richard Henderson.

Here is the virus zika under the “eye” cryoelectron microscopy.

Viral particles in vitrified water – the first image obtained by Dubose in 1984 (Illustration: Nobelprize.org.)

The structure of a protein molecule obtained using cryo-EM on the left with the resolution that was available until 2013, to the right, with a resolution reached after 2013. (Illustration: Nobelprize.org.)”

To know exactly how to work cell molecules and molecular complexes to study in detail their structure. But until recently, not all biomolecules can be seen, existing visualization methods often proved powerless here . Widely used in molecular biology x-ray crystallography is also not always gives such an opportunity. The problem is that the molecules and their complexes have to be placed in environments that are very different from the conditions of a living cell, and in this environment, the molecule may change their shape (undergo a conformational change), and to appear before our eyes is not in the form in which it operates “live”. In addition, the same x-ray crystallography requires crystallizing a biological sample, which is not always possible.

Cryoelectron microscopy (cryo-EM). which this year was given the Nobel prize in chemistry, has significantly expanded in this sense, the capability of researchers. With its help it is possible to see many molecular processes, and therefore more deeply understand the chemistry of a living organism, without which it is impossible, for example, to develop new, more effective drugs.

In cryo-EM biological sample was examined at very low temperatures – usually at the temperature of liquid nitrogen. In conventional electron microscopy image gives us a powerful electron beam, which can easily damage the biological sample, on the other hand, in the high vacuum of the electron microscope, the water evaporates very quickly, and biomolecules and their complexes, deprived of the natural water environment changes the structure and destroyed.

Initially, cryogenic electron microscopy was developed to protect the sample from damage due to radiation and desiccation. In the early 1980-ies, a Swiss biologist Jacques Dubose (Jacques Dubochet) suggested placing bioblasts in hardened water. But “hardened” does not simply means “frozen”. Dubose developed a method for the glass transition of water: it has cooled it so fast that during the solidification of water around the sample maintained the structure, which was in liquid form. The biomolecule contained in a “stekloregistr”, retains its natural shape even under vacuum conditions.

Almost at the same time, between the years 1975-1986, German biophysicist, Frank Joachim (Joachim Frank) was engaged in that tried to find a way out of a very muddy two-dimensional images obtained in the electron microscope to make three-dimensional image microscopium structure. In the end, he managed to develop a method based on the comparison and analysis of two-dimensional electronic images, and this method is widely used still.

Scottish biologist Richard Henderson (Richard Henderson) in 1990, using cryo-EM for the first time received three-dimensional image of the protein bacteriorhodopsin with the atomic resolution.

Since cryoelectron microscopy has been continuously improved, and finally, in 2015 published an article where they were presented with a map of the bacterial enzyme beta-galactosidase with a resolution of 2.2 Å (one Angstrom is the approximate diameter of the electron orbits in the hydrogen atom). Method cryoelectron microscopy has become routine in recent years, the scientific literature abounds with images of the most different three-dimensional structures of proteins, causing resistance to antibiotics, the virus to Zeke.

 

According to the materials of the Nobel Committee.