Deoxyribonucleic acid, DNA, is known by a series of nucleotides that carry genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. The most well-known structure of the DNA molecule consists of two strands that interact with one another forming a double helix. Telomeric sequences and promotion regions exhibit guanine-rich regions, which are important in the processes of aging and regulation of gene expression. These sequence properties and their functions are associated with structures consisting of four strands known as G-quadruplex. Nuclear magnetic resonance, NMR, enables studies of correlations between molecular structure of DNA and its biological activities or mode of action. NMR center at NIC has determined and published in international journals new quadruplex structures adopted by guanine-rich regions of DNA fragments thus contributing to understanding of their roles in neurodevelopment and neurological disorders, abnormalities in bone and cartilage development, cancer as well as basic cellular processes.