Keywords
Abstract
The review presents the history of discovery and study, as well as modern data on the structure, properties
and functions of quadruplexes (G4) – the most studied non-canonical secondary structures of nucleic acids. In the genomes of all three domains of life – archaea, bacteria/viruses and eukaryotes – quadruplexes are found, they are distributed non-randomly and play a pleiotropic role in many DNA and RNA transactions. G4s not only inhibit and/or initiate gene expression, but also control genome stability, depending on their specif- ic location. The conditions of G4 folding and unfolding processes, which in normal cells are temporary and effectively controlled by enzymes – helicases, mutations of which are associated with the development of oncological, neurodegenerative and other diseases, are discussed.
G4-RNA structures, like their G4-DNA counterparts, are very dynamic and play an important role in many molecular processes, among which are the most significant functions of mRNA – translation, splicing, polyadenylation and termination. It is quite obvious that G4-RNAs are more attractive and suitable for influences of pharmacological agents as target molecules, since they differ from G4-DNA in parallel topology, less hydration, but greater compactness and thermodynamic stability.
Small molecule-ligands of natural and/or artificial origin that stabilize G4 structures are considered pro- mising pharmacological agents that effectively affect many intracellular processes in both humans and pathogens.