Nucleic Acid Aptamers
Aptamers are strands of nucleic acids capable of folding into highly organised, complex structures allowing ligation to molecular targets at high affinity
The development of aptamer technology stems from the understanding that nucleic acids are not simply carriers of genetic information. They are also capable of carrying out complex molecular interactions and are involved in many biological processes including riboswitches, ribozymes, tRNAs, ribosome binding sites and indeed the majority of the ribosome itself.
Aptamers are short single-stranded nucleic acid oligomers (DNA or RNA) with sequence-dependent structures, characterized by stems, loops, bulges, hairpins, pseudoknots, triplexes, or quadruplexes. These simple secondary structures can fold further to give complex tertiary structures, allowing aptamers to form complementary shapes wrapping around all or part of their target (small molecules) or to fit snugly into clefts and gaps within the surface of much larger targets. This structural complementarity facilitates formation of electrostatic interactions or hydrogen bonds between the aptamer and its target, as well as stacking interactions between aromatic compounds and the nucleobases. This ability to fold into or around a target means that it is should be theoretically possible to select specific aptamers to almost any given target.
Aptamers have been successfully raised to almost every type of organic compound, including:
- Inorganic and small organic molecules
- Peptides & proteins
- Complex targets – cells, viruses, microorganisms, tissue sections