American physicists have modeled the shear load of twelve molecules of glycine between the virtual diamond anvils using chemical analysis, they found a lot of heavy molecules and an unknown condensation reaction of three molecules of glycine in the dimer and triol, which flows only under the shear load. The article, which was simulated prebiotic synthesis of molecules of glycine at the impact of the meteorite, published in the journal Chemical Science.
The origin of life on our planet (and potentially on other planets) is not fully understood — nowadays there are many theories, how did the first biological structure in the conditions of ancient Earth. For the formation of complex protein structures in the extreme conditions of the required building material — amino acids. The simplest amino acid — glycine have been found in meteorites and comets. Many authors offered their own versions of the formation of proteins from amino acids: for example, this could be caused by underwater hydrothermal sources, as well as the fall of meteorites.
Scientists have conducted experiments and simulations of shock compressions of amino acids. For example, at a pressure of from 5 to 21 gigapascal and in the temperature interval 412-870 Kelvin of glycine obtained dimers, and at 26 GPA and a temperature of 77 Kelvin glycine and alanine is reacted with the formation of trimers. But under less severe conditions of dry glycine at a pressure of 5-100 megapascals obtained oligomers up to ten glycine units, but in the course of such a reaction requires a month. The region of influence of shear loads on the prebiotic synthesis is still intact, although locally they can lower the activation energy and thereby speed up the reactions.
Brad Steele (Brad A. Steele) with colleagues from Lawrence Livermore national laboratory Lawrence used the method of rotating the virtual diamond anvils using molecular dynamics modelling. This approach of simulation is more realistic than work for the same purpose, but in which the shear load was applied to the simulated virtual periodic lattice.
To perform the simulation, physicists have used the method of self-consistent strong connection of the functional of charge density. While diamond anvil consisted of two 2D-periodic crystals of diamond with the boundary hydrogen atoms on the faces (111) — this configuration was chosen to reduce the contribution of the dipole moment on the surface of the anvils. Between the diamond anvils placed 12 molecules of glycine with a random orientation. To increase the pressure, the scientists reduced the distance between the anvils, where one is rotated by compression. Scientists chose two speeds of rotation: one half Angstrom per picosecond, which corresponds to the shear velocity at impact of a meteorite (physicists sought the upper boundary of the possible in terms of Land).