An international think-tank, which consisted of scientist from Russian and Germany, used a technique of cryoelectron microscopy for taking images of a ribosome, a cell protein-making “plant”, during its work. Scientists followed a trajectory of RNA molecules inside a ribosome and reported results of their work in Nature magazine.

Protein synthesis is a very complicated process, which is executed at a ribosome, special cell organelle. Protein structure is transcribed to molecules of messenger RNA from DNA template. A ribosome translates this information and uses transport RNA molecules to build a polypeptide chain, which later becomes a protein molecule.

The mechanism of protein biosynthesis has been under careful attention of biologists for over 50 years, however, many aspects of the process still remain unclear. One of the most intriguing questions is how translocation (a simultaneous transition of one molecule of mRNA and two molecules of tRNA in a ribosome) happens. In a cell, translocation should be performed with extremely high accuracy, since even a single mistake leads to a synthesis of non-functional polypeptide, and many mistakes may cause cell death, biologists comment.

 

 

Scientists have observed a process of translocation in a ribosome of an enteric bacterium Escherichia coli by means of cryoelectron microscopy. This technique allows studying objects by means of an electron microscope under extremely low temperatures, about -200 degrees Centigrade. Authors of the research say that previously use techniques of X-ray crystallography and electron microscopy detected only initial and final positions of tRNA, giving no information about trajectory of its fast movements.

Details of how transport RNA moved in a ribosome became clear only after scientists dared to combine developments of several scientific laboratories. Using specially treated ribosome complexes, researchers slowed down the process of translocation and reversed it, thus being able to make suitable samples for microscopy on various stages of the reaction.

Researchers received over 50 consecutive images of a ribosome during a translocation process and used them for building ribosome’s 3D model. Therefore, scientists successfully described a fast and accurate process of translocation of RNA and ribosome, as well as showed that the technique they have used – cryoelectron microscopy – provided unique possibilities for studying mechanisms of cell functioning on macromolecular level.

Fantastic work of Russian and German scientists revealed important and intriguing aspects of interactions between rapidly changing ribosomal forms and its function, controlled by elongation factor, Nature paper reviewer (Mans Ehrenberg from Uppsala University) said.

Authors of the research believe that studying mechanisms of translocation during protein synthesis is not only fundamental scientific task. Knowing details of this process may help improving existing antibiotics and developing new ones.

Sources: RIA Novosti

Kizilova Anna