A bouquet of DNA structures: Emerging diversity

Abstract

Structural polymorphism of DNA has constantly been evolving from the time of illustration of the double helical model of DNA by Watson and Crick. A variety of non-canonical DNA structures have constantly been documented across the globe. DNA attracted worldwide attention as a carrier of genetic information. In addition to the classical Watson–Crick duplex, DNA can actually adopt diverse structures during its active participation in cellular processes like replication, transcription, recombination and repair. Structures like hairpin, cruciform, triplex, G-triplex, quadruplex, i-motif and other alternative non-canonical DNA structures have been studied at length and have also shown their in vivo occurrence. This review mainly focuses on non-canonical structures adopted by DNA oligonucleotides which have certain prerequisites for their formation in terms of sequence, its length, number and orientation of strands along with varied solution conditions. This conformational polymorphism of DNA might be the basis of different functional properties of a specific set of DNA sequences, further giving some insights for various extremely complicated biological phenomena. Many of these structures have already shown their linkages with diseases like cancer and genetic disorders, hence making them an extremely striking target for structure-specific drug designing and therapeutic applications.

Binding Studies of Metal–Salphen and Metal–Bipyridine Complexes towards G‐Quadruplex DNA

“…Besides its canonical double‐stranded helix, DNA can fold into a range of different structures such as hairpins, triplexes, cruciform junctions, i ‐motifs and G‐quadruplexes (G4) . The latter forms from stacks of two or more guanine tetrads that in turn arise from hydrogen bonding network of four guanines (see Figure ).…”

DNA Conformation Regulates Gene Expression: The MYC Promoter and Beyond

“…Z‐DNA has also been detected at nucleosomes as a result of SWI/SNF remodeling activity . Additional non‐B‐DNA secondary structures can form as a result of base pairing of opposite DNA strands not occurring sequentially; these include melted single‐stranded DNA, hairpin, triplex, and quadruplex structures . Importantly, we are beginning to understand the roles of such non‐canonical structures in the normal cellular context, and association between aberrant DNA conformation, genome instability and development of disease .…”

Genome and stress-reaction in animals and humans

“…Они могут изменять доступность ДНК для белков, при-нимающих участие в контроле экспрессии генов [7,8]. Конформационная динамика ДНК отражает процессы регуляции генной активности на уровне генома.…”