ИСТИНА

One of popular of research direction in molecular medicine is a design and use of synthetic oligonucleotides (including modified ones) with the potential for the formation of non-canonical forms of nucleic acids (NK) to regulate cellular processes also known as aptamers. However some difficulties in studying G-quadruplex aptamers in vivo are associated with the fact that it is difficult to know what conformation an aptamer takes under certain conditions. X-ray crystallography is unable to answer this question due to its limitations as well as fact that it works with crystals but not solutions. Small-angle X- ray scattering (SAXS) can be used as an alternative method for studying a structure of small oligonucleotides in solution (aptamers). Unlike X-ray diffraction analysis, which requires the aptamer to be in the form of a clear, stable crystal, which is not always possible for small 3D-unit oligonucleotides and NMR, where excessive temperature can prevent the aptamer from adopting one clear conformation, using SAXS can avoid these problems. The aim of this work is to study the 3D structures of DNA aptamers, thrombin inhibitors. The main tasks of the work were the revealing of three-dimensional models of the structures of the RE31, NU172, HD22 aptamers using the small-angle X-ray scattering method.