Could a cheap molecule used to disinfect swimming pools provide the key to creating a new form of DNA nanomaterials?
Cyanuric acid is commonly used to stabilize chlorine in backyard pools; it binds to free chlorine and releases it slowly in the water. But researchers at McGill University have now discovered that this same small, inexpensive molecule can also be used to coax DNA into forming a brand new structure: instead of forming the familiar double helix, DNA’s nucleobases -- which normally form rungs in the DNA ladder -- associate with cyanuric acid molecules to form a triple helix.
Ref: Reprogramming the assembly of unmodified DNA with a small molecule. Nature Chemistry (22 February 2016) | DOI: 10.1038/nchem.2451
The ability of DNA to store and encode information arises from base pairing of the four-letter nucleobase code to form a double helix. Expanding this DNA ‘alphabet’ by synthetic incorporation of new bases can introduce new functionalities and enable the formation of novel nucleic acid structures. However, reprogramming the self-assembly of existing nucleobases presents an alternative route to expand the structural space and functionality of nucleic acids. Here we report the discovery that a small molecule, cyanuric acid, with three thymine-like faces, reprogrammes the assembly of unmodified poly(adenine) (poly(A)) into stable, long and abundant fibres with a unique internal structure. Poly(A) DNA, RNA and peptide nucleic acid (PNA) all form these assemblies. Our studies are consistent with the association of adenine and cyanuric acid units into a hexameric rosette, which brings together poly(A) triplexes with a subsequent cooperative polymerization. Fundamentally, this study shows that small hydrogen-bonding molecules can be used to induce the assembly of nucleic acids in water, which leads to new structures from inexpensive and readily available materials.