海角社区

By Chris Chipello, 海角社区 Newsroom

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 海角社区 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鈥檚 nucleobases -- which normally form rungs in the DNA ladder -- associate with cyanuric acid molecules to form a triple helix.

The discovery 鈥渄emonstrates a fundamentally new way to make DNA assemblies,鈥� says Hanadi Sleiman, Canada Research Chair in DNA Nanoscience at 海角社区 and senior author of the study, published in Nature Chemistry. 鈥淭his concept may apply to many other molecules, and the resulting DNA assemblies could have applications in a range of technologies.鈥�

The DNA alphabet, composed of the four letters A, T, G and C, is the underlying code that gives rise to the double helix famously discovered by Watson and Crick more than 60 years ago. The letters, or bases, of DNA can also interact in other ways to form a variety of DNA structures used by scientists in nanotechnology applications 鈥� quite apart from DNA鈥檚 biological role in living cells.

For years, scientists have sought to develop a larger, designer alphabet of DNA bases that would enable the creation of more DNA structures with unique, new properties. For the most part, however, devising these new molecules has involved costly and complex procedures.

The road to the 海角社区 team鈥檚 discovery began some eight years ago, when Sleiman mentioned to others in her lab that cyanuric acid might be worth experimenting with because of its properties. The molecule has three faces with the same binding features as thymine (T in the DNA alphabet), the natural complement to adenine (A).聽 鈥淥ne of my grad students tried it,鈥� she recalls, 鈥渁nd came back and said he saw fibres鈥� through an atomic force microscope.

The researchers later discovered that these fibres have a unique underlying structure. Cyanuric acid is able to coax strands composed of adenine bases into forming a novel motif in DNA assembly. The adenine and cyanuric acid units associate into flower-like rosettes; these form the cross-section of a triple helix.聽 The strands then combine to form long fibres.

鈥淭he nanofibre material formed in this way is easy to access, abundant and highly structured,鈥� says Nicole Avakyan, a PhD student in Sleiman鈥檚 lab and first author of the study. 鈥淲ith further development, we can envisage a variety of applications of this material, from medicinal chemistry to tissue engineering and materials science.鈥�

Funding for the research was provided by the Natural Sciences and Engineering Research Council of Canada, the Canada Research Chairs Program, the Canada Foundation for Innovation, the Centre for Self-Assembled Chemical Structures, and the Fonds Qu茅b茅cois de la Recherche sur la Nature et les Technologies.

鈥淩eprogramming the assembly of unmodified DNA with a small molecule,鈥� Nicole Avakyan et al, Nature Chemistry, published online Feb. 22, 2016. doi:10.1038/nchem.2451

CAPTION:聽The interaction of adenine bases strung together into short DNA strands with the small molecule cyanuric acid leads to the formation of a unique rosette motif. This association brings about the assembly of triple helixes that further polymerize into longer fibres.

IMAGE CREDIT: Nicole Avakyan