Nucleic acid analogues are compounds which are
analogous (structurally similar) to naturally occurring
RNA and
DNA, used in medicine and in molecular biology research.
Nucleic acids are chains of nucleotides, which are composed of three parts: a
phosphate backbone, a pucker-shaped pentose sugar, either
ribose or
deoxyribose, and one of four
nucleobases. An analogue may have any of these altered. Typically the analogue nucleobases confer, among other things, different base pairing and base stacking properties. Examples include universal bases, which can pair with all four canonical bases, and phosphate-sugar backbone analogues such as
PNA, which affect the properties of the chain (PNA can even form a
triple helix). Nucleic acid analogues are also called
Xeno Nucleic Acid and represent one of the main pillars of
xenobiology, the design of new-to-nature forms of life based on alternative biochemistries.