The studies of biological and biomimetic systems are important not only for fundamental science but also for the design of drugs and materials. High-pressure research related to biological applications is a rapidly developing field. Investigation of macromolecules, however, is challenging. Crystals of smaller fragments  are therefore often studied, in order to get quantitative information on the effect of pressure on selected hydrogen bonds and motions of the intramolecular fragments. Crystals built of small RNA, or DNA fragments can serve to model the effect of pressure on nucleic acids and oligonucleotides, similar to how the crystals of amino acids are used to model the properties of peptides. In the present contribution I give an overview of high-pressure studies of crystalline amino acids, nucleobases, their salts and complexes by single-crystal X-ray diffraction, Raman spectroscopy and optical microscopy. The role of kinetic and thermodynamic factors on polymorphic transitions is discussed, as well as relations between the anisotropy of lattice strain and intermolecular interactions. 

The research is presently supported by Russian Ministry of Science and Education, project АААА-А19-119020890025-3.